{"id":858,"date":"2025-02-18T18:40:23","date_gmt":"2025-02-18T10:40:23","guid":{"rendered":"https:\/\/eve2333.top\/?p=858"},"modified":"2025-02-18T18:40:24","modified_gmt":"2025-02-18T10:40:24","slug":"mysql%e6%95%b0%e6%8d%ae%e5%ba%93%e5%85%a5%e9%97%a8%e5%88%b0%e5%a4%a7%e8%9b%87%e5%b0%9a%e7%a1%85%e8%b0%b7%e5%ae%8b%e7%ba%a2%e5%ba%b7%e8%80%81%e5%b8%88%e7%ac%94%e8%ae%b0-%e5%9f%ba%e7%a1%80%e7%af%87-pa-9","status":"publish","type":"post","link":"https:\/\/eve2333.top\/?p=858","title":{"rendered":"MySQL\u6570\u636e\u5e93\u5165\u95e8\u5230\u5927\u86c7\u5c1a\u7845\u8c37\u5b8b\u7ea2\u5eb7\u8001\u5e08\u7b14\u8bb0 \u57fa\u7840\u7bc7 part 12"},"content":{"rendered":"\n

 \u7b2c12\u7ae0_MySQL\u6570\u636e\u7c7b\u578b\u7cbe\u8bb2<\/h1>\n\n\n\n

\u7b2c\u4e09\u7ae0\u5230\u7b2c10\u7ae0\u662fDDL\uff0c\u7b2c11\u7ae0\u662fDML\uff0c\u63a5\u4e0b\u6765\u5c31\u662fDCL\u4e86\uff0cTCL\u4e4b\u7c7b\u7684\u5427<\/p>\n\n\n\n

\u7c7b\u578b<\/td>\u7c7b\u578b\u4e3e\u4f8b<\/td><\/tr>
\u6574\u6570\u7c7b\u578b<\/td>TINYINT\u3001SMALLINT\u3001MEDIUMINT\u3001INT(\u6216INTEGER)\u3001BIGINT<\/td><\/tr>
\u6d6e\u70b9\u7c7b\u578b<\/td>FLOAT\u3001DOUBLE<\/td><\/tr>
\u5b9a\u70b9\u6570\u7c7b\u578b<\/td>DECIMAL                                             \u94f6\u884c\u4e00\u822c\u90fd\u662f\u7528decimal<\/td><\/tr>
\u4f4d\u7c7b\u578b<\/td>BIT<\/td><\/tr>
\u65e5\u671f\u65f6\u95f4\u7c7b\u578b<\/td>YEAR\u3001TIME\u3001DATE\u3001DATETIME\u3001TIMESTAMP<\/td><\/tr>
\u6587\u672c\u5b57\u7b26\u4e32\u7c7b\u578b<\/td>CHAR\u3001VARCHAR\u3001TINYTEXT\u3001TEXT\u3001MEDIUMTEXT\u3001LONGTEXT<\/td><\/tr>
\u679a\u4e3e\u7c7b\u578b<\/td>ENUM                            \u679a\u4e3e\uff08\u591a\u9009\u4e00\uff09<\/td><\/tr>
\u96c6\u5408\u7c7b\u578b<\/td>SET                                \u96c6\u5408\uff08\u591a\u9009\u591a\uff09<\/td><\/tr>
\u4e8c\u8fdb\u5236\u5b57\u7b26\u4e32\u7c7b\u578b<\/td>BINARY\u3001VARBINARY\u3001TINYBLOB\u3001BLOB\u3001MEDIUMBLOB\u3001LONGBLOB<\/td><\/tr>
JSON\u7c7b\u578b<\/td>JSON\u5bf9\u8c61\u3001JSON\u6570\u7ec4<\/td><\/tr>
\u7a7a\u95f4\u6570\u636e\u7c7b\u578b<\/td>\u5355\u503c\u7c7b\u578b\uff1aGEOMETRY\u3001POINT\u3001LINESTRING\u3001POLYGON\uff1b \u96c6\u5408\u7c7b\u578b\uff1aMULTIPOINT\u3001MULTILINESTRING\u3001MULTIPOLYGON\u3001 GEOMETRYCOLLECTION<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

 \u5e38\u89c1\u6570\u636e\u7c7b\u578b\u7684\u5c5e\u6027\uff0c\u5982\u4e0b\uff1a<\/p>\n\n\n\n

# \u672c\u7ae0\u7684\u5185\u5bb9\u6d4b\u8bd5\u5efa\u8bae\u4f7f\u7528 MySQL5.7\u8fdb\u884c\u6d4b\u8bd5\u3002<\/strong><\/p>\n\n\n\n

#1.\u5173\u4e8e\u5c5e\u6027\uff1acharacter set name\n\nSHOW VARIABLES LIKE 'character_%';\n\n#\u521b\u5efa\u6570\u636e\u5e93\u65f6\u6307\u540d\u5b57\u7b26\u96c6\nCREATE DATABASE IF NOT EXISTS dbtest12 CHARACTER SET 'utf8';\n\nSHOW CREATE DATABASE dbtest12;\n\n#\u521b\u5efa\u8868\u7684\u65f6\u5019\uff0c\u6307\u540d\u8868\u7684\u5b57\u7b26\u96c6\nCREATE TABLE temp(\nid INT\n) CHARACTER SET 'utf8';\n\nSHOW CREATE TABLE temp;\n\n#\u521b\u5efa\u8868\uff0c\u6307\u540d\u8868\u4e2d\u7684\u5b57\u6bb5\u65f6\uff0c\u53ef\u4ee5\u6307\u5b9a\u5b57\u6bb5\u7684\u5b57\u7b26\u96c6\nCREATE TABLE temp1(\nid INT,\nNAME VARCHAR(15) CHARACTER SET 'gbk'\n\n);\nSHOW CREATE TABLE temp1;<\/code><\/pre>\n\n\n\n
 59-MySQL\u6570\u636e\u7c7b\u578b\u6982\u8ff0_\u5b57\u7b26\u96c6\u8bbe\u7f6e_\u54d4\u54e9\u54d4\u54e9_bilibili<\/a><\/p>\n\n\n\n
 2. \u6574\u6570\u7c7b\u578b<\/h2>\n\n\n\n
\u6574\u6570\u7c7b\u578b\u4e00\u5171\u6709 5 \u79cd\uff0c\u5305\u62ec TINYINT\u3001SMALLINT\u3001MEDIUMINT\u3001INT\uff08INTEGER\uff09\u548c BIGINT\u3002<\/p>\n\n\n\n
\u7c7b\u578b<\/th>\u4f4d\u6570<\/th>\u6709\u7b26\u53f7\u8303\u56f4<\/th>\u65e0\u7b26\u53f7\u8303\u56f4<\/th><\/tr><\/thead>
TINYINT<\/td>1<\/td>-128~127<\/td>0~255<\/td><\/tr>
SMALLINT<\/td>2<\/td>-32768~32767<\/td>0~65535<\/td><\/tr>
MEDIUMINT<\/td>3<\/td>-8388608~8388607<\/td>0~16777215<\/td><\/tr>
INT, INTEGER<\/td>4<\/td>-2147483648~2147483647<\/td>0~4294967295<\/td><\/tr>
BIGINT<\/td>8<\/td>-9223372036854775808~9223372036854775807<\/td>0~18446744073709551615<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
#2.\u6574\u578b\u6570\u636e\u7c7b\u578b\n\nUSE dbtest12;\n\nCREATE TABLE test_int1(\nf1 TINYINT,\nf2 SMALLINT,\nf3 MEDIUMINT,\nf4 INTEGER,\nf5 BIGINT\n\n);\n\nDESC test_int1;\n\nINSERT INTO test_int1(f1)\nVALUES(12),(-12),(-128),(127);\n\nSELECT * FROM test_int1;\n\n#Out of range value for column 'f1' at row 1\nINSERT INTO test_int1(f1)\nVALUES(128);\n\nCREATE TABLE test_int2(\nf1 INT,\nf2 INT(5),\nf3 INT(5) ZEROFILL  #\u2460 \u663e\u793a\u5bbd\u5ea6\u4e3a5\u3002\u5f53insert\u7684\u503c\u4e0d\u8db35\u4f4d\u65f6\uff0c\u4f7f\u75280\u586b\u5145\u3002 \u2461\u5f53\u4f7f\u7528ZEROFILL\u65f6\uff0c\u81ea\u52a8\u4f1a\u6dfb\u52a0UNSIGNED\n)\n<\/code><\/pre>\n\n\n\n
\u6574\u6570\u7c7b\u578b\u7684\u53ef\u9009\u5c5e\u6027\u6709\u4e09\u4e2a\uff1a\u7b2c\u4e00\u4e2a\u662f M<\/p>\n\n\n\n
M : \u8868\u793a\u663e\u793a\u5bbd\u5ea6\uff0cM\u7684\u53d6\u503c\u8303\u56f4\u662f(0, 255)\u3002\u4f8b\u5982\uff0cint(5)\uff1a\u5f53\u6570\u636e\u5bbd\u5ea6\u5c0f\u4e8e5\u4f4d\u7684\u65f6\u5019\u5728\u6570\u5b57\u524d\u9762\u9700\u8981\u7528 \u5b57\u7b26\u586b\u6ee1\u5bbd\u5ea6\u3002\u8be5\u9879\u529f\u80fd\u9700\u8981\u914d\u5408\u201c ZEROFILL \u201d\u4f7f\u7528\uff0c\u8868\u793a\u7528\u201c0\u201d\u586b\u6ee1\u5bbd\u5ea6\uff0c\u5426\u5219\u6307\u5b9a\u663e\u793a\u5bbd\u5ea6\u65e0\u6548\u3002<\/p>\n\n\n\n
\u5982\u679c\u8bbe\u7f6e\u4e86\u663e\u793a\u5bbd\u5ea6\uff0c\u90a3\u4e48\u63d2\u5165\u7684\u6570\u636e\u5bbd\u5ea6\u8d85\u8fc7\u663e\u793a\u5bbd\u5ea6\u9650\u5236\uff0c\u4f1a\u4e0d\u4f1a\u622a\u65ad\u6216\u63d2\u5165\u5931\u8d25\uff1f
\u7b54\u6848\uff1a\u4e0d\u4f1a\u5bf9\u63d2\u5165\u7684\u6570\u636e\u6709\u4efb\u4f55\u5f71\u54cd\uff0c\u8fd8\u662f\u6309\u7167\u7c7b\u578b\u7684\u5b9e\u9645\u5bbd\u5ea6\u8fdb\u884c\u4fdd\u5b58\uff0c\u5373 \u663e\u793a\u5bbd\u5ea6\u4e0e\u7c7b\u578b\u53ef\u4ee5\u5b58\u50a8\u7684 \u503c\u8303\u56f4\u65e0\u5173\u3002\u4eceMySQL 8.0.17\u5f00\u59cb\uff0c\u6574\u6570\u6570\u636e\u7c7b\u578b\u4e0d\u63a8\u8350\u4f7f\u7528\u663e\u793a\u5bbd\u5ea6\u5c5e\u6027\u3002<\/strong><\/p>\n\n\n\n
\u6574\u578b\u6570\u636e\u7c7b\u578b\u53ef\u4ee5\u5728\u5b9a\u4e49\u8868\u7ed3\u6784\u65f6\u6307\u5b9a\u6240\u9700\u8981\u7684\u663e\u793a\u5bbd\u5ea6\uff0c\u5982\u679c\u4e0d\u6307\u5b9a\uff0c\u5219\u7cfb\u7edf\u4e3a\u6bcf\u4e00\u79cd\u7c7b\u578b\u6307\u5b9a\u9ed8\u8ba4 \u7684\u5bbd\u5ea6\u503c 
TINYINT\u6709\u7b26\u53f7\u6570\u548c\u65e0\u7b26\u53f7\u6570\u7684\u53d6\u503c\u8303\u56f4\u5206\u522b\u4e3a-128~127\u548c0~255\uff0c\u7531\u4e8e\u8d1f\u53f7\u5360\u4e86\u4e00\u4e2a\u6570\u5b57\u4f4d\uff0c\u56e0\u6b64 TINYINT\u9ed8\u8ba4\u7684\u663e\u793a\u5bbd\u5ea6\u4e3a4\u3002\u540c\u7406\uff0c\u5176\u4ed6\u6574\u6570\u7c7b\u578b\u7684\u9ed8\u8ba4\u663e\u793a\u5bbd\u5ea6\u4e0e\u5176\u6709\u7b26\u53f7\u6570\u7684\u6700\u5c0f\u503c\u7684\u5bbd\u5ea6\u76f8\u540c\u3002<\/p>\n\n\n\n
INSERT INTO test_int2(f1,f2)\nVALUES(123,123),(123456,123456);\n\nSELECT * FROM test_int2;\n\nINSERT INTO test_int2(f3)\nVALUES(123),(123456);\n\nSHOW CREATE TABLE test_int2;\n\n\nCREATE TABLE test_int3(\nf1 INT UNSIGNED\n);\n\nDESC test_int3;\n\nINSERT INTO test_int3\nVALUES(2412321);\n\n#Out of range value for column 'f1' at row 1\nINSERT INTO test_int3\nVALUES(4294967296);<\/code><\/pre>\n\n\n\n
2. UNSIGNED : \u65e0\u7b26\u53f7\u7c7b\u578b\uff08\u975e\u8d1f\uff09\uff0c\u6240\u6709\u7684\u6574\u6570\u7c7b\u578b\u90fd\u6709\u4e00\u4e2a\u53ef\u9009\u7684\u5c5e\u6027UNSIGNED\uff08\u65e0\u7b26\u53f7\u5c5e\u6027\uff09\uff0c\u65e0 \u7b26\u53f7\u6574\u6570\u7c7b\u578b\u7684\u6700\u5c0f\u53d6\u503c\u4e3a0\u3002\u6240\u4ee5\uff0c\u5982\u679c\u9700\u8981\u5728MySQL\u6570\u636e\u5e93\u4e2d\u4fdd\u5b58\u975e\u8d1f\u6574\u6570\u503c\u65f6\uff0c\u53ef\u4ee5\u5c06\u6574\u6570\u7c7b\u578b\u8bbe \u7f6e\u4e3a\u65e0\u7b26\u53f7\u7c7b\u578b\u3002<\/p>\n\n\n\n
int\u7c7b\u578b\u9ed8\u8ba4\u663e\u793a\u5bbd\u5ea6\u4e3aint(11)\uff0c\u65e0\u7b26\u53f7int\u7c7b\u578b\u9ed8\u8ba4\u663e\u793a\u5bbd\u5ea6\u4e3aint(10)\u3002<\/p>\n\n\n\n
3. ZEROFILL : 0\u586b\u5145,\uff08\u5982\u679c\u67d0\u5217\u662fZEROFILL\uff0c\u90a3\u4e48MySQL\u4f1a\u81ea\u52a8\u4e3a\u5f53\u524d\u5217\u6dfb\u52a0UNSIGNED\u5c5e\u6027\uff09\uff0c\u5982\u679c\u6307 \u5b9a\u4e86ZEROFILL\u53ea\u662f\u8868\u793a\u4e0d\u591fM\u4f4d\u65f6\uff0c\u75280\u5728\u5de6\u8fb9\u586b\u5145\uff0c\u5982\u679c\u8d85\u8fc7M\u4f4d\uff0c\u53ea\u8981\u4e0d\u8d85\u8fc7\u6570\u636e\u5b58\u50a8\u8303\u56f4\u5373\u53ef\u3002<\/p>\n\n\n\n
\u539f\u6765\uff0c\u5728 int(M) \u4e2d\uff0cM \u7684\u503c\u8ddf int(M) \u6240\u5360\u591a\u5c11\u5b58\u50a8\u7a7a\u95f4\u5e76\u65e0\u4efb\u4f55\u5173\u7cfb\u3002 int(3)\u3001int(4)\u3001int(8) \u5728\u78c1\u76d8\u4e0a\u90fd \u662f\u5360\u7528 4 bytes \u7684\u5b58\u50a8\u7a7a\u95f4\u3002\u4e5f\u5c31\u662f\u8bf4\uff0cint(M)\uff0c\u5fc5\u987b\u548cUNSIGNED ZEROFILL\u4e00\u8d77\u4f7f\u7528\u624d\u6709\u610f\u4e49\u3002\u5982\u679c\u6574 \u6570\u503c\u8d85\u8fc7M\u4f4d\uff0c\u5c31\u6309\u7167\u5b9e\u9645\u4f4d\u6570\u5b58\u50a8\u3002\u53ea\u662f\u65e0\u987b\u518d\u7528\u5b57\u7b26 0 \u8fdb\u884c\u586b\u5145\u3002 <\/p>\n\n\n\n
\n
TINYINT \uff1a\u4e00\u822c\u7528\u4e8e\u679a\u4e3e\u6570\u636e\uff0c\u6bd4\u5982\u7cfb\u7edf\u8bbe\u5b9a\u53d6\u503c\u8303\u56f4\u5f88\u5c0f\u4e14\u56fa\u5b9a\u7684\u573a\u666f\u3002<\/p>\n\n\n\n
SMALLINT \uff1a\u53ef\u4ee5\u7528\u4e8e\u8f83\u5c0f\u8303\u56f4\u7684\u7edf\u8ba1\u6570\u636e\uff0c\u6bd4\u5982\u7edf\u8ba1\u5de5\u5382\u7684\u56fa\u5b9a\u8d44\u4ea7\u5e93\u5b58\u6570\u91cf\u7b49\u3002 MEDIUMINT \uff1a\u7528\u4e8e\u8f83\u5927\u6574\u6570\u7684\u8ba1\u7b97\uff0c\u6bd4\u5982\u8f66\u7ad9\u6bcf\u65e5\u7684\u5ba2\u6d41\u91cf\u7b49\u3002<\/p>\n\n\n\n
INT\u3001INTEGER \uff1a\u53d6\u503c\u8303\u56f4\u8db3\u591f\u5927\uff0c\u4e00\u822c\u60c5\u51b5\u4e0b\u4e0d\u7528\u8003\u8651\u8d85\u9650\u95ee\u9898\uff0c\u7528\u5f97\u6700\u591a\u3002\u6bd4\u5982\u5546\u54c1\u7f16\u53f7\u3002<\/p>\n\n\n\n
BIGINT \uff1a\u53ea\u6709\u5f53\u4f60\u5904\u7406\u7279\u522b\u5de8\u5927\u7684\u6574\u6570\u65f6\u624d\u4f1a\u7528\u5230\u3002\u6bd4\u5982\u53cc\u5341\u4e00\u7684\u4ea4\u6613\u91cf\u3001\u5927\u578b\u95e8\u6237\u7f51\u7ad9\u70b9\u51fb\u91cf\u3001\u8bc1 \u5238\u516c\u53f8\u884d\u751f\u4ea7\u54c1\u6301\u4ed3\u7b49\u3002<\/p>\n<\/blockquote>\n\n\n\n
3. \u6d6e\u70b9\u7c7b\u578b <\/h2>\n\n\n\n
\u6d6e\u70b9\u6570\u548c\u5b9a\u70b9\u6570\u7c7b\u578b\u7684\u7279\u70b9\u662f\u53ef\u4ee5 \u5904\u7406\u5c0f\u6570\uff0c\u4f60\u53ef\u4ee5\u628a\u6574\u6570\u770b\u6210\u5c0f\u6570\u7684\u4e00\u4e2a\u7279\u4f8b\u3002\u56e0\u6b64\uff0c\u6d6e\u70b9\u6570\u548c\u5b9a\u70b9 \u6570\u7684\u4f7f\u7528\u573a\u666f\uff0c\u6bd4\u6574\u6570\u5927\u591a\u4e86\u3002 MySQL\u652f\u6301\u7684\u6d6e\u70b9\u6570\u7c7b\u578b\uff0c\u5206\u522b\u662f FLOAT\u3001DOUBLE\u3001REAL\u3002 FLOAT \u8868\u793a\u5355\u7cbe\u5ea6\u6d6e\u70b9\u6570\uff1b DOUBLE \u8868\u793a\u53cc\u7cbe\u5ea6\u6d6e\u70b9\u6570\uff1b<\/p>\n\n\n\n
REAL\u9ed8\u8ba4\u5c31\u662f DOUBLE\u3002\u5982\u679c\u4f60\u628a SQL \u6a21\u5f0f\u8bbe\u5b9a\u4e3a\u542f\u7528\u201c REAL_AS_FLOAT \u201d\uff0c\u90a3 \u4e48\uff0cMySQL \u5c31\u8ba4\u4e3a REAL \u662f FLOAT\u3002\u5982\u679c\u8981\u542f\u7528\u201cREAL_AS_FLOAT\u201d\uff0c\u53ef\u4ee5\u901a\u8fc7\u4ee5\u4e0b SQL \u8bed\u53e5\u5b9e\u73b0\uff1a
SET sql_mode = \u201cREAL_AS_FLOAT\u201d; <\/p>\n\n\n\n
\"\"<\/p>\n\n\n\n
\n
\u95ee\u98981\uff1aFLOAT \u548c DOUBLE \u8fd9\u4e24\u79cd\u6570\u636e\u7c7b\u578b\u7684\u533a\u522b\u662f\u5565\u5462\uff1f<\/p>\n\n\n\n
FLOAT \u5360\u7528\u5b57\u8282\u6570\u5c11\uff0c\u53d6\u503c\u8303\u56f4\u5c0f\uff1bDOUBLE \u5360\u7528\u5b57\u8282\u6570\u591a\uff0c\u53d6\u503c\u8303\u56f4\u4e5f\u5927\u3002<\/p>\n\n\n\n
\u95ee\u98982\uff1a\u4e3a\u4ec0\u4e48\u6d6e\u70b9\u6570\u7c7b\u578b\u7684\u65e0\u7b26\u53f7\u6570\u53d6\u503c\u8303\u56f4\uff0c\u53ea\u76f8\u5f53\u4e8e\u6709\u7b26\u53f7\u6570\u53d6\u503c\u8303\u56f4\u7684\u4e00\u534a\uff0c\u4e5f\u5c31\u662f\u53ea\u76f8\u5f53\u4e8e \u6709\u7b26\u53f7\u6570\u53d6\u503c\u8303\u56f4\u5927\u4e8e\u7b49\u4e8e\u96f6\u7684\u90e8\u5206\u5462\uff1f<\/p>\n\n\n\n
MySQL \u5b58\u50a8\u6d6e\u70b9\u6570\u7684\u683c\u5f0f\u4e3a\uff1a \u7b26\u53f7(S) \u3001 \u5c3e\u6570(M) \u548c \u9636\u7801(E) \u3002\u56e0\u6b64\uff0c\u65e0\u8bba\u6709\u6ca1\u6709\u7b26\u53f7\uff0cMySQL \u7684\u6d6e\u70b9\u6570\u90fd\u4f1a\u5b58\u50a8\u8868\u793a\u7b26\u53f7\u7684\u90e8\u5206\u3002\u56e0\u6b64\uff0c \u6240\u8c13\u7684\u65e0\u7b26\u53f7\u6570\u53d6\u503c\u8303\u56f4\uff0c\u5176\u5b9e\u5c31\u662f\u6709\u7b26\u53f7\u6570\u53d6\u503c\u8303\u56f4\u5927\u4e8e\u7b49\u4e8e\u96f6\u7684\u90e8\u5206\u3002<\/p>\n<\/blockquote>\n\n\n\n
    \n
  • \u00a0\u5bf9\u4e8e\u6d6e\u70b9\u7c7b\u578b\uff0c\u5728MySQL\u4e2d\u5355\u7cbe\u5ea6\u503c\u4f7f\u75284\u4e2a\u5b57\u8282\uff0c\u53cc\u7cbe\u5ea6\u503c\u4f7f\u75288\u4e2a\u5b57\u8282\u3002<\/li>\n\n\n\n
  • MySQL\u5141\u8bb8\u4f7f\u7528 FLOAT(M,D) \u6216 \u975e\u6807\u51c6\u8bed\u6cd5\uff08\u5176\u4ed6\u6570\u636e\u5e93\u672a\u5fc5\u652f\u6301\uff0c\u56e0\u6b64\u5982\u679c\u6d89\u53ca\u5230\u6570\u636e\u8fc1\u79fb\uff0c\u5219\u6700\u597d\u4e0d\u8981\u8fd9\u4e48 \u7528\uff09\uff1a DOUBLE(M,D) \u3002\u8fd9\u91cc\uff0cM\u79f0\u4e3a \u4f4d\uff0cD=\u5c0f\u6570\u4f4d\u3002 D<=M<=255\uff0c0<=D<=30\u3002 \u7cbe\u5ea6\uff0cD\u79f0\u4e3a \u6807\u5ea6\u3002(M,D)\u4e2d M=\u6574\u6570\u4f4d+\u5c0f\u6570 \u4f8b\u5982\uff0c\u5b9a\u4e49\u4e3aFLOAT(5,2)\u7684\u4e00\u4e2a\u5217\u53ef\u4ee5\u663e\u793a\u4e3a-999.99-999.99\u3002\u5982\u679c\u8d85\u8fc7\u8fd9\u4e2a\u8303\u56f4\u4f1a\u62a5\u9519\u3002<\/li>\n\n\n\n
  • FLOAT\u548cDOUBLE\u7c7b\u578b\u5728\u4e0d\u6307\u5b9a(M,D)\u65f6\uff0c\u9ed8\u8ba4\u4f1a\u6309\u7167\u5b9e\u9645\u7684\u7cbe\u5ea6\uff08\u7531\u5b9e\u9645\u7684\u786c\u4ef6\u548c\u64cd\u4f5c\u7cfb\u7edf\u51b3\u5b9a\uff09 \u6765\u663e\u793a\u3002<\/li>\n\n\n\n
  • \u8bf4\u660e\uff1a\u6d6e\u70b9\u7c7b\u578b\uff0c\u4e5f\u53ef\u4ee5\u52a0 UNSIGNED \uff0c\u4f46\u662f\u4e0d\u4f1a\u6539\u53d8\u6570\u636e\u8303\u56f4\uff0c\u4f8b\u5982\uff1aFLOAT(3,2) UNSIGNED\u4ecd\u7136 \u53ea\u80fd\u8868\u793a0-9.99\u7684\u8303\u56f4\u3002<\/li>\n\n\n\n
  • \u4e0d\u7ba1\u662f\u5426\u663e\u5f0f\u8bbe\u7f6e\u4e86\u7cbe\u5ea6(M,D)\uff0c\u8fd9\u91ccMySQL\u7684\u5904\u7406\u65b9\u6848\u5982\u4e0b\uff1a\n
      \n
    • \u5982\u679c\u5b58\u50a8\u65f6\uff0c\u6574\u6570\u90e8\u5206\u8d85\u51fa\u4e86\u8303\u56f4\uff0cMySQL\u5c31\u4f1a\u62a5\u9519\uff0c\u4e0d\u5141\u8bb8\u5b58\u8fd9\u6837\u7684\u503c<\/li>\n\n\n\n
    • \u5982\u679c\u5b58\u50a8\u65f6\uff0c\u5c0f\u6570\u70b9\u90e8\u5206\u82e5\u8d85\u51fa\u8303\u56f4\uff0c\u5c31\u5206\u4ee5\u4e0b\u60c5\u51b5\uff1a
      \u200b\u200b\u200b\u200b\u200b
      \u82e5\u56db\u820d\u4e94\u5165\u540e\uff0c\u6574\u6570\u90e8\u5206\u6ca1\u6709\u8d85\u51fa\u8303\u56f4\uff0c\u5219\u53ea\u8b66\u544a\uff0c\u4f46\u80fd\u6210\u529f\u64cd\u4f5c\u5e76\u56db\u820d\u4e94\u5165\u5220\u9664\u591a\u4f59 \u7684\u5c0f\u6570\u4f4d\u540e\u4fdd\u5b58\u3002\u4f8b\u5982\u5728FLOAT(5,2)\u5217\u5185\u63d2\u5165999.009\uff0c\u8fd1\u4f3c\u7ed3\u679c\u662f999.01\u3002

      \u82e5\u56db\u820d\u4e94\u5165\u540e\uff0c\u6574\u6570\u90e8\u5206\u8d85\u51fa\u8303\u56f4\uff0c\u5219MySQL\u62a5\u9519\uff0c\u5e76\u62d2\u7edd\u5904\u7406\u3002\u5982FLOAT(5,2)\u5217\u5185\u63d2\u5165 999.995\u548c-999.995\u90fd\u4f1a\u62a5\u9519\u3002<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n
      \u4eceMySQL 8.0.17\u5f00\u59cb\uff0cFLOAT(M,D) \u548cDOUBLE(M,D)\u7528\u6cd5\u5728\u5b98\u65b9\u6587\u6863\u4e2d\u5df2\u7ecf\u660e\u786e\u4e0d\u63a8\u8350\u4f7f\u7528\uff0c\u5c06\u6765\u53ef \u80fd\u88ab\u79fb\u9664\u3002\u53e6\u5916\uff0c\u5173\u4e8e\u6d6e\u70b9\u578bFLOAT\u548cDOUBLE\u7684UNSIGNED\u4e5f\u4e0d\u63a8\u8350\u4f7f\u7528\u4e86\uff0c\u5c06\u6765\u4e5f\u53ef\u80fd\u88ab\u79fb\u9664\u3002 <\/p>\n\n\n\n
      #3.\u6d6e\u70b9\u7c7b\u578b\nCREATE TABLE test_double1(\nf1 FLOAT,\nf2 FLOAT(5,2),\nf3 DOUBLE,\nf4 DOUBLE(5,2)\n);\n\nDESC test_double1;\n\nINSERT INTO test_double1(f1,f2)\nVALUES(123.45,123.45);\n\nSELECT * FROM test_double1;\n\nINSERT INTO test_double1(f3,f4)\nVALUES(123.45,123.456); #\u5b58\u5728\u56db\u820d\u4e94\u5165\n\n#Out of range value for column 'f4' at row 1\nINSERT INTO test_double1(f3,f4)\nVALUES(123.45,1234.456);\n\n#Out of range value for column 'f4' at row 1\nINSERT INTO test_double1(f3,f4)\nVALUES(123.45,999.995);\n\n#\u6d4b\u8bd5FLOAT\u548cDOUBLE\u7684\u7cbe\u5ea6\u95ee\u9898\nCREATE TABLE test_double2(\nf1 DOUBLE\n);\n\nINSERT INTO test_double2\nVALUES(0.47),(0.44),(0.19);\n\nSELECT SUM(f1)\nFROM test_double2;\n\nSELECT SUM(f1) = 1.1,1.1 = 1.1\nFROM test_double2;<\/code><\/pre>\n\n\n\n
      \u6d6e\u70b9\u6570\u7c7b\u578b\u6709\u4e2a\u7f3a\u9677\uff0c\u5c31\u662f\u4e0d\u7cbe\u51c6\u3002\u4e0b\u9762\u6211\u6765\u91cd\u70b9\u89e3\u91ca\u4e00\u4e0b\u4e3a\u4ec0\u4e48 MySQL \u7684\u6d6e\u70b9\u6570\u4e0d\u591f\u7cbe\u51c6\u3002\u6bd4\u5982\uff0c\u6211\u4eec\u8bbe\u8ba1\u4e00\u4e2a\u8868\uff0c\u6709f1\u8fd9\u4e2a\u5b57\u6bb5\uff0c\u63d2\u5165\u503c\u5206\u522b\u4e3a0.47,0.44,0.19\uff0c\u6211\u4eec\u671f\u5f85\u7684\u8fd0\u884c\u7ed3\u679c\u662f\uff1a0.47 + 0.44 + 0.19 = 1.1\u3002\u800c\u4f7f\u7528sum\u4e4b\u540e\u67e5\u8be2\uff1a\u67e5\u8be2\u7ed3\u679c\u662f 1.0999999999999999\u3002<\/p>\n\n\n\n
      MySQL \u7528 4 \u4e2a\u5b57\u8282\u5b58\u50a8 FLOAT \u7c7b\u578b\u6570\u636e\uff0c\u7528 8 \u4e2a\u5b57\u8282\u6765\u5b58\u50a8 DOUBLE \u7c7b\u578b\u6570\u636e\u3002\u65e0\u8bba\u54ea\u4e2a\uff0c\u90fd\u662f\u91c7\u7528\u4e8c \u8fdb\u5236\u7684\u65b9\u5f0f\u6765\u8fdb\u884c\u5b58\u50a8\u7684\u3002\u6bd4\u5982 9.625\uff0c\u7528\u4e8c\u8fdb\u5236\u6765\u8868\u8fbe\uff0c\u5c31\u662f 1001.101\uff0c\u6216\u8005\u8868\u8fbe\u6210 1.001101\u00d72^3\u3002\u5982 \u679c\u5c3e\u6570\u4e0d\u662f 0 \u6216 5\uff08\u6bd4\u5982 9.624\uff09\uff0c\u4f60\u5c31\u65e0\u6cd5\u7528\u4e00\u4e2a\u4e8c\u8fdb\u5236\u6570\u6765\u7cbe\u786e\u8868\u8fbe\u3002\u8fdb\u800c\uff0c\u5c31\u53ea\u597d\u5728\u53d6\u503c\u5141\u8bb8\u7684\u8303 \u56f4\u5185\u8fdb\u884c\u56db\u820d\u4e94\u5165\u3002<\/p>\n\n\n\n
      \u5728\u7f16\u7a0b\u4e2d\uff0c\u5982\u679c\u7528\u5230\u6d6e\u70b9\u6570\uff0c\u8981\u7279\u522b\u6ce8\u610f\u8bef\u5dee\u95ee\u9898\uff0c\u56e0\u4e3a\u6d6e\u70b9\u6570\u662f\u4e0d\u51c6\u786e\u7684\uff0c\u6240\u4ee5\u6211\u4eec\u8981\u907f\u514d\u4f7f\u7528\u201c=\u201d\u6765 \u5224\u65ad\u4e24\u4e2a\u6570\u662f\u5426\u76f8\u7b49\u3002<\/strong>\u540c\u65f6\uff0c\u5728\u4e00\u4e9b\u5bf9\u7cbe\u786e\u5ea6\u8981\u6c42\u8f83\u9ad8\u7684\u9879\u76ee\u4e2d\uff0c\u5343\u4e07\u4e0d\u8981\u4f7f\u7528\u6d6e\u70b9\u6570\uff0c\u4e0d\u7136\u4f1a\u5bfc\u81f4\u7ed3 \u679c\u9519\u8bef\uff0c\u751a\u81f3\u662f\u9020\u6210\u4e0d\u53ef\u633d\u56de\u7684\u635f\u5931\u3002\u90a3\u4e48\uff0cMySQL \u6709\u6ca1\u6709\u7cbe\u51c6\u7684\u6570\u636e\u7c7b\u578b\u5462\uff1f\u5f53\u7136\u6709\uff0c\u8fd9\u5c31\u662f\u5b9a\u70b9\u6570 \u7c7b\u578b\uff1a DECIMAL \u3002<\/p>\n\n\n\n
       4. \u5b9a\u70b9\u6570\u7c7b\u578b<\/h2>\n\n\n\n
      \u6570\u636e\u7c7b\u578b<\/td>\u5b57\u8282\u6570<\/td>\u542b\u4e49<\/td><\/tr>
        DECIMAL(M,D),DEC,NUMERIC<\/td>M+2\u5b57\u8282<\/td>\u6709\u6548\u8303\u56f4\u7531M\u548cD\u51b3\u5b9a<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
      #4. \u5b9a\u70b9\u6570\u7c7b\u578b\nCREATE TABLE test_decimal1(\nf1 DECIMAL,\nf2 DECIMAL(5,2)\n);\n\nDESC test_decimal1;\n\nINSERT INTO test_decimal1(f1)\nVALUES(123),(123.45);\n\nSELECT * FROM test_decimal1;\n\nINSERT INTO test_decimal1(f2)\nVALUES(999.99);\n\nINSERT INTO test_decimal1(f2)\nVALUES(67.567);#\u5b58\u5728\u56db\u8272\u4e94\u5165\n\n#Out of range value for column 'f2' at row 1\nINSERT INTO test_decimal1(f2)\nVALUES(1267.567);\n\n#Out of range value for column 'f2' at row 1\nINSERT INTO test_decimal1(f2)\nVALUES(999.995);\n\n#\u6f14\u793aDECIMAL\u66ff\u6362DOUBLE\uff0c\u4f53\u73b0\u7cbe\u5ea6\nALTER TABLE test_double2\nMODIFY f1 DECIMAL(5,2);\n\nDESC test_double2;\n\nSELECT SUM(f1)\nFROM test_double2;\n\nSELECT SUM(f1) = 1.1,1.1 = 1.1\nFROM test_double2;<\/code><\/pre>\n\n\n\n
      \u4f7f\u7528 DECIMAL(M,D) \u7684\u65b9\u5f0f\u8868\u793a\u9ad8\u7cbe\u5ea6\u5c0f\u6570\u3002\u5176\u4e2d\uff0cM \u88ab\u79f0\u4e3a\u7cbe\u5ea6\uff0cD \u88ab\u79f0\u4e3a\u6807\u5ea6\u30020<=M<=65\uff0c0<=D<=30\uff0cD<M\u3002\u4f8b\u5982\uff0c\u5b9a\u4e49 DECIMAL\uff085,2\uff09\u7684\u7c7b\u578b\uff0c\u8868\u793a\u8be5\u5217\u53d6\u503c\u8303\u56f4\u662f -999.99~999.99\u3002
      DECIMAL(M,D) \u7684\u6700\u5927\u53d6\u503c\u8303\u56f4\u4e0e DOUBLE \u7c7b\u578b\u4e00\u6837\uff0c\u4f46\u662f\u6709\u6548\u7684\u6570\u636e\u8303\u56f4\u662f\u7531 M \u548c D \u51b3\u5b9a\u7684\u3002
      DECIMAL \u7684\u5b58\u50a8\u7a7a\u95f4\u5e76\u4e0d\u662f\u56fa\u5b9a\u7684\uff0c\u7531\u7cbe\u5ea6\u503c M \u51b3\u5b9a\uff0c\u603b\u5171\u5360\u7528\u7684\u5b58\u50a8\u7a7a\u95f4\u4e3a M+2 \u4e2a\u5b57\u8282\u3002\u4e5f\u5c31\u662f\u8bf4\uff0c\u5728\u4e00\u4e9b\u5bf9\u7cbe\u5ea6\u8981\u6c42\u4e0d\u9ad8\u7684\u573a\u666f\u4e0b\uff0c\u6bd4\u8d77\u5360\u7528\u540c\u6837\u5b57\u8282\u957f\u5ea6\u7684\u5b9a\u70b9\u6570\uff0c\u6d6e\u70b9\u6570\u8868\u8fbe\u7684\u6570\u503c\u8303\u56f4\u53ef\u4ee5\u66f4\u5927\u4e00\u4e9b\u3002
      \u5b9a\u70b9\u6570\u5728 MySQL \u5185\u90e8\u662f\u4ee5 \u5b57\u7b26\u4e32 \u7684\u5f62\u5f0f\u8fdb\u884c\u5b58\u50a8\uff0c\u8fd9\u5c31\u51b3\u5b9a\u4e86\u5b83\u4e00\u5b9a\u662f\u7cbe\u786e\u7684\u3002
      \u5f53 DECIMAL \u7c7b\u578b\u4e0d\u6307\u5b9a\u7cbe\u5ea6\u548c\u6807\u5ea6\u65f6\uff0c\u5176\u9ed8\u8ba4\u4e3a DECIMAL(10,0)\u3002\u5f53\u6570\u636e\u7684\u7cbe\u5ea6\u8d85\u51fa\u4e86\u5b9a\u70b9\u6570\u7c7b\u578b\u7684\u7cbe\u5ea6\u8303\u56f4\u65f6\uff0c\u5219 MySQL \u540c\u6837\u4f1a\u8fdb\u884c\u56db\u820d\u4e94\u5165\u5904\u7406\u3002
      \u6d6e\u70b9\u6570 vs \u5b9a\u70b9\u6570
      - \u6d6e\u70b9\u6570\u76f8\u5bf9\u4e8e\u5b9a\u70b9\u6570\u7684\u4f18\u70b9\u662f\u5728\u957f\u5ea6\u4e00\u5b9a\u7684\u60c5\u51b5\u4e0b\uff0c\u6d6e\u70b9\u7c7b\u578b\u53d6\u503c\u8303\u56f4\u5927\uff0c\u4f46\u662f\u4e0d\u7cbe\u51c6\uff0c\u9002\u7528\u4e8e\u9700\u8981\u53d6\u503c\u8303\u56f4\u5927\uff0c\u53c8\u53ef\u4ee5\u5bb9\u5fcd\u5fae\u5c0f\u8bef\u5dee\u7684\u79d1\u5b66\u8ba1\u7b97\u573a\u666f\uff08\u6bd4\u5982\u8ba1\u7b97\u5316\u5b66\u3001\u5206\u5b50\u5efa\u6a21\u3001\u6d41\u4f53\u52a8\u529b\u5b66\u7b49\uff09
      - \u5b9a\u70b9\u6570\u7c7b\u578b\u53d6\u503c\u8303\u56f4\u76f8\u5bf9\u5c0f\uff0c\u4f46\u662f\u7cbe\u51c6\uff0c\u6ca1\u6709\u8bef\u5dee\uff0c\u9002\u5408\u4e8e\u5bf9\u7cbe\u5ea6\u8981\u6c42\u6781\u9ad8\u7684\u573a\u666f\uff08\u6bd4\u5982\u6d89\u53ca\u91d1\u989d\u8ba1\u7b97\u7684\u573a\u666f\uff09<\/p>\n\n\n\n
      \n
       \u201c\u7531\u4e8e DECIMAL \u6570\u636e\u7c7b\u578b\u7684\u7cbe\u51c6\u6027\uff0c\u5728\u6211\u4eec\u7684\u9879\u76ee\u4e2d\uff0c\u9664\u4e86\u6781\u5c11\u6570\uff08\u6bd4\u5982\u5546\u54c1\u7f16\u53f7\uff09\u7528\u5230\u6574\u6570\u7c7b\u578b\u5916\uff0c\u5176\u4ed6\u7684\u6570\u503c\u90fd\u7528\u7684\u662f DECIMAL\uff0c\u539f\u56e0\u5c31\u662f\u8fd9\u4e2a\u9879\u76ee\u6240\u5904\u7684\u96f6\u552e\u884c\u4e1a\uff0c\u8981\u6c42\u7cbe\u51c6\uff0c\u4e00\u5206\u94b1\u4e5f\u4e0d\u80fd\u5dee\u3002 \u201d \u2014\u2014\u6765\u81ea\u67d0\u9879\u76ee\u7ecf\u7406<\/p>\n<\/blockquote>\n\n\n\n
      5. \u4f4d\u7c7b\u578b\uff1aBIT<\/h2>\n\n\n\n
       BIT\u7c7b\u578b\u4e2d\u5b58\u50a8\u7684\u662f\u4e8c\u8fdb\u5236\u503c\uff0c\u7c7b\u4f3c010110\u3002<\/p>\n\n\n\n
      \u4e8c\u8fdb\u5236\u5b57\u7b26\u4e32\u7c7b\u578b<\/td>\u957f\u5ea6<\/td>\u957f\u5ea6\u8303\u56f4<\/td>\u5360\u7528\u7a7a\u95f4<\/td><\/tr>
      BIT(M)<\/td>M<\/td>1<=M<=64<\/td>\u7ea6\u4e3a (M+7)\/8 \u4e2a\u5b57\u8282<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
      \"\"<\/p>\n\n\n\n
      #5. \u4f4d\u7c7b\u578b\uff1aBIT\nCREATE TABLE test_bit1(\nf1 BIT,\nf2 BIT(5),\nf3 BIT(64)\n);\n\nDESC test_bit1;\n\nINSERT INTO test_bit1(f1)\nVALUES(0),(1);\n\nSELECT *\nFROM test_bit1;\n\n#Data too long for column 'f1' at row 1\nINSERT INTO test_bit1(f1)\nVALUES(2);\n\nINSERT INTO test_bit1(f2)\nVALUES(31);\n\n#Data too long for column 'f2' at row 1\nINSERT INTO test_bit1(f2)\nVALUES(32);\n\nSELECT BIN(f1),BIN(f2),HEX(f1),HEX(f2)\nFROM test_bit1;\n\n#\u6b64\u65f6+0\u4ee5\u540e\uff0c\u53ef\u4ee5\u4ee5\u5341\u8fdb\u5236\u7684\u65b9\u5f0f\u663e\u793a\u6570\u636e\nSELECT f1 + 0, f2 + 0\nFROM test_bit1;<\/code><\/pre>\n\n\n\n
      \u6ce8\u610f\uff1a\u5728\u5411BIT\u7c7b\u578b\u7684\u5b57\u6bb5\u4e2d\u63d2\u5165\u6570\u636e\u65f6\uff0c\u4e00\u5b9a\u8981\u786e\u4fdd\u63d2\u5165\u7684\u6570\u636e\u5728BIT\u7c7b\u578b\u652f\u6301\u7684\u8303\u56f4\u5185\u3002\u4f7f\u7528SELECT\u547d\u4ee4\u67e5\u8be2\u4f4d\u5b57\u6bb5\u65f6\uff0c\u53ef\u4ee5\u7528 BIN() \u6216 HEX() \u51fd\u6570\u8fdb\u884c\u8bfb\u53d6\u3002<\/p>\n\n\n\n
      6. \u65e5\u671f\u4e0e\u65f6\u95f4\u7c7b\u578b<\/h2>\n\n\n\n
      YEAR\u7c7b\u578b<\/h3>\n\n\n\n
       MySQL\u6709\u591a\u79cd\u8868\u793a\u65e5\u671f\u548c\u65f6\u95f4\u7684\u6570\u636e\u7c7b\u578b\uff0c\u4e0d\u540c\u7684\u7248\u672c\u53ef\u80fd\u6709\u6240\u5dee\u5f02\uff0cMySQL8.0\u7248\u672c\u652f\u6301\u7684\u65e5\u671f\u548c\u65f6\u95f4 \u7c7b\u578b\u4e3b\u8981\u6709\uff1aYEAR\u7c7b\u578b\u3001TIME\u7c7b\u578b\u3001DATE\u7c7b\u578b\u3001DATETIME\u7c7b\u578b\u548cTIMESTAMP\u7c7b\u578b\u3002<\/p>\n\n\n\n
        \n
      1. YEAR \u7c7b\u578b\u901a\u5e38\u7528\u6765\u8868\u793a\u5e74<\/li>\n\n\n\n
      2. DATE \u7c7b\u578b\u901a\u5e38\u7528\u6765\u8868\u793a\u5e74\u3001\u6708\u3001\u65e5<\/li>\n\n\n\n
      3. TIME \u7c7b\u578b\u901a\u5e38\u7528\u6765\u8868\u793a\u65f6\u3001\u5206\u3001\u79d2<\/li>\n\n\n\n
      4. DATETIME \u7c7b\u578b\u901a\u5e38\u7528\u6765\u8868\u793a\u5e74\u3001\u6708\u3001\u65e5\u3001\u65f6\u3001\u5206\u3001\u79d2<\/li>\n\n\n\n
      5. TIMESTAMP \u7c7b\u578b\u901a\u5e38\u7528\u6765\u8868\u793a\u5e26\u65f6\u533a\u7684\u5e74\u3001\u6708\u3001\u65e5\u3001\u65f6\u3001\u5206\u3001\u79d2<\/li>\n<\/ol>\n\n\n\n
        \u7c7b\u578b<\/th>\u540d\u79f0<\/th>\u5b57\u8282<\/th>\u65e5\u671f\u683c\u5f0f<\/th>\u6700\u5c0f\u503c<\/th>\u6700\u5927\u503c<\/th><\/tr><\/thead>
        YEAR<\/td>\u5e74<\/td>1<\/td>YYYY\u6216YY<\/td>1901<\/td>2155<\/td><\/tr>
        TIME<\/td>\u65f6\u95f4<\/td>3<\/td>HH:MM:SS<\/td>-838:59:59<\/td>838:59:59<\/td><\/tr>
        DATE<\/td>\u65e5\u671f<\/td>3<\/td>YYYY-MM-DD<\/td>1000-01-01<\/td>9999-12-03<\/td><\/tr>
        DATETIME<\/td>\u65e5\u671f\u65f6\u95f4<\/td>8<\/td>YYYY-MM-DD HH:MM:SS<\/td>1000-01-01 00:00:00<\/td>9999-12-31 23:59:59<\/td><\/tr>
        TIMESTAMP<\/td>\u65e5\u671f\u65f6\u95f4<\/td>4<\/td>YYYY-MM-DD HH:MM:SS<\/td>1970-01-01 00:00:00 UTC<\/td>2038-01-19 03:14:07 UTC<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
         YEAR\u7c7b\u578b\u7528\u6765\u8868\u793a\u5e74\u4efd\uff0c\u5728\u6240\u6709\u7684\u65e5\u671f\u65f6\u95f4\u7c7b\u578b\u4e2d\u6240\u5360\u7528\u7684\u5b58\u50a8\u7a7a\u95f4\u6700\u5c0f\uff0c\u53ea\u9700\u8981 1\u4e2a\u5b57\u8282\u7684\u5b58\u50a8\u7a7a\u95f4\u3002<\/p>\n\n\n\n
        \u5728MySQL\u4e2d\uff0cYEAR\u6709\u4ee5\u4e0b\u51e0\u79cd\u5b58\u50a8\u683c\u5f0f\uff1a<\/p>\n\n\n\n
        \u4ee54\u4f4d\u5b57\u7b26\u4e32\u6216\u6570\u5b57\u683c\u5f0f\u8868\u793aYEAR\u7c7b\u578b\uff0c\u5176\u683c\u5f0f\u4e3aYYYY\uff0c\u6700\u5c0f\u503c\u4e3a1901\uff0c\u6700\u5927\u503c\u4e3a2155\u3002
        \u4ee52\u4f4d\u5b57\u7b26\u4e32\u683c\u5f0f\u8868\u793aYEAR\u7c7b\u578b\uff0c\u6700\u5c0f\u503c\u4e3a00\uff0c\u6700\u5927\u503c\u4e3a99\u3002 \u5f53\u53d6\u503c\u4e3a01\u523069\u65f6\uff0c\u8868\u793a2001\u52302069\uff1b \u5f53\u53d6\u503c\u4e3a70\u523099\u65f6\uff0c\u8868\u793a1970\u52301999\uff1b \u5f53\u53d6\u503c\u6574\u6570\u76840\u621600\u6dfb\u52a0\u7684\u8bdd\uff0c\u90a3\u4e48\u662f0000\u5e74\uff1b \u5f53\u53d6\u503c\u662f\u65e5\u671f\/\u5b57\u7b26\u4e32\u7684'0'\u6dfb\u52a0\u7684\u8bdd\uff0c\u662f2000\u5e74\u3002<\/p>\n\n\n\n
        \u4eceMySQL5.5.27\u5f00\u59cb\uff0c2\u4f4d\u683c\u5f0f\u7684YEAR\u5df2\u7ecf\u4e0d\u63a8\u8350\u4f7f\u7528\u3002YEAR\u9ed8\u8ba4\u683c\u5f0f\u5c31\u662f\u201cYYYY\u201d\uff0c\u6ca1\u5fc5\u8981\u5199\u6210YEAR(4)\uff0c \u4eceMySQL 8.0.19\u5f00\u59cb\uff0c\u4e0d\u63a8\u8350\u4f7f\u7528\u6307\u5b9a\u663e\u793a\u5bbd\u5ea6\u7684YEAR(4)\u6570\u636e\u7c7b\u578b\u3002\u65f6\u4ee3\u7684\u773c\u6cea<\/p>\n\n\n\n
        #6.1 YEAR\u7c7b\u578b\nCREATE TABLE test_year(\nf1 YEAR,\nf2 YEAR(4)\n);\n\nDESC test_year;\n\nINSERT INTO test_year(f1)\nVALUES('2021'),(2022);\n\nSELECT * FROM test_year;\n\nINSERT INTO test_year(f1)\nVALUES ('2155');\n\n#Out of range value for column 'f1' at row 1\nINSERT INTO test_year(f1)\nVALUES ('2156');\n\nINSERT INTO test_year(f1)\nVALUES ('69'),('70');\n\nINSERT INTO test_year(f1)\nVALUES (0),('00');<\/code><\/pre>\n\n\n\n
        DATE\u7c7b\u578b<\/h3>\n\n\n\n
        DATE\u7c7b\u578b\u8868\u793a\u65e5\u671f\uff0c\u6ca1\u6709\u65f6\u95f4\u90e8\u5206\uff0c\u683c\u5f0f\u4e3a YYYY-MM-DD \u9700\u8981 3\u4e2a\u5b57\u8282\u7684\u5b58\u50a8\u7a7a\u95f4<\/p>\n\n\n\n
        \u4f7f\u7528 CURRENT_DATE() \u6216\u8005 NOW() \u51fd\u6570\uff0c\u4f1a\u63d2\u5165\u5f53\u524d\u7cfb\u7edf\u7684\u65e5\u671f\u3002<\/p>\n\n\n\n
        CREATE TABLE test_date1(\nf1 DATE\n);\n\nDESC test_date1;\n\nINSERT INTO test_date1\nVALUES ('2020-10-01'), ('20201001'),(20201001);\n\nINSERT INTO test_date1\nVALUES ('00-01-01'), ('000101'), ('69-10-01'), ('691001'), ('70-01-01'), ('700101'), ('99-01-01'), ('990101');\n\nINSERT INTO test_date1\nVALUES (000301), (690301), (700301), (990301); #\u5b58\u5728\u9690\u5f0f\u8f6c\u6362<\/code><\/pre>\n\n\n\n
        <\/p>\n\n\n\n
        INSERT INTO test_date1\nVALUES (CURDATE()),(CURRENT_DATE()),(NOW());\n\nSELECT *\nFROM test_date1;<\/code><\/pre>\n\n\n\n
        6.3 TIME\u7c7b\u578b<\/h3>\n\n\n\n
        TIME\u7c7b\u578b\u7528\u6765\u8868\u793a\u65f6\u95f4\uff0c\u4e0d\u5305\u542b\u65e5\u671f\u90e8\u5206\u3002\u5728MySQL\u4e2d\uff0c\u9700\u8981 3\u4e2a\u5b57\u8282\u7684\u5b58\u50a8\u7a7a\u95f4\u6765\u5b58\u50a8TIME\u7c7b\u578b\u7684\u6570 \u636e\uff0c\u53ef\u4ee5\u4f7f\u7528\u201cHH:MM:SS\u201d\u683c\u5f0f\u6765\u8868\u793aTIME\u7c7b\u578b\u3002<\/p>\n\n\n\n
        \u5728MySQL\u4e2d\uff0c\u5411TIME\u7c7b\u578b\u7684\u5b57\u6bb5\u63d2\u5165\u6570\u636e\u65f6\uff0c\u4e5f\u53ef\u4ee5\u4f7f\u7528\u51e0\u79cd\u4e0d\u540c\u7684\u683c\u5f0f\u3002<\/p>\n\n\n\n
          \n
        • \uff081\uff09\u53ef\u4ee5\u4f7f\u7528\u5e26\u6709\u5192\u53f7\u7684 \u5b57\u7b26\u4e32\uff0c\u6bd4\u5982' D HH:MM:SS' \u3001' HH:MM:SS '\u3001' HH:MM '\u3001' D HH:MM '\u3001' D HH '\u6216' SS '\u683c\u5f0f\uff0c\u90fd\u80fd\u88ab\u6b63 \u786e\u5730\u63d2\u5165TIME\u7c7b\u578b\u7684\u5b57\u6bb5\u4e2d\u3002\u5176\u4e2dD\u8868\u793a\u5929\uff0c\u5176\u6700\u5c0f\u503c\u4e3a0\uff0c\u6700\u5927\u503c\u4e3a34\u3002\u5982\u679c\u4f7f\u7528\u5e26\u6709D\u683c\u5f0f\u7684\u5b57\u7b26\u4e32 \u63d2\u5165TIME\u7c7b\u578b\u7684\u5b57\u6bb5\u65f6\uff0cD\u4f1a\u88ab\u8f6c\u5316\u4e3a\u5c0f\u65f6\uff0c\u8ba1\u7b97\u683c\u5f0f\u4e3aD*24+HH\u3002\u5f53\u4f7f\u7528\u5e26\u6709\u5192\u53f7\u5e76\u4e14\u4e0d\u5e26D\u7684\u5b57\u7b26\u4e32 \u8868\u793a\u65f6\u95f4\u65f6\uff0c\u8868\u793a\u5f53\u5929\u7684\u65f6\u95f4\uff0c\u6bd4\u598212:10\u8868\u793a12:10:00\uff0c\u800c\u4e0d\u662f00:12:10\u3002<\/li>\n\n\n\n
        • \uff082\uff09\u53ef\u4ee5\u4f7f\u7528\u4e0d\u5e26\u6709\u5192\u53f7\u7684 \u5b57\u7b26\u4e32\u6216\u8005\u6570\u5b57\uff0c\u683c\u5f0f\u4e3a' HHMMSS '\u6216\u8005 HHMMSS \u3002\u5982\u679c\u63d2\u5165\u4e00\u4e2a\u4e0d\u5408\u6cd5\u7684\u5b57\u7b26\u4e32\u6216\u8005\u6570\u5b57\uff0cMySQL\u5728\u5b58 \u50a8\u6570\u636e\u65f6\uff0c\u4f1a\u5c06\u5176\u81ea\u52a8\u8f6c\u5316\u4e3a00:00:00\u8fdb\u884c\u5b58\u50a8\u3002\u6bd4\u59821210\uff0cMySQL\u4f1a\u5c06\u6700\u53f3\u8fb9\u7684\u4e24\u4f4d\u89e3\u6790\u6210\u79d2\uff0c\u8868\u793a 00:12:10\uff0c\u800c\u4e0d\u662f12:10:00\u3002<\/li>\n\n\n\n
        • \uff083\uff09\u4f7f\u7528 CURRENT_TIME() \u6216\u8005 NOW() \uff0c\u4f1a\u63d2\u5165\u5f53\u524d\u7cfb\u7edf\u7684\u65f6\u95f4\u3002\u00a0<\/li>\n<\/ul>\n\n\n\n
          CREATE TABLE test_time1(\nf1 TIME\n);\n\nDESC test_time1;\n\nINSERT INTO test_time1\nVALUES('2 12:30:29'), ('12:35:29'), ('12:40'), ('2 12:40'),('1 05'), ('45');\n\nINSERT INTO test_time1\nVALUES ('123520'), (124011),(1210);\n\nINSERT INTO test_time1\nVALUES (NOW()), (CURRENT_TIME()),(CURTIME());\n\nSELECT *\nFROM test_time1;<\/code><\/pre>\n\n\n\n
          6.4 DATETIME\u7c7b\u578b<\/h3>\n\n\n\n
          DATETIME\u7c7b\u578b\u5728\u6240\u6709\u7684\u65e5\u671f\u65f6\u95f4\u7c7b\u578b\u4e2d\u5360\u7528\u7684\u5b58\u50a8\u7a7a\u95f4\u6700\u5927\uff0c\u603b\u5171\u9700\u89818\u4e2a\u5b57\u8282\u7684\u5b58\u50a8\u7a7a\u95f4\u3002\u5728\u683c\u5f0f\u4e0a \u4e3aDATE\u7c7b\u578b\u548cTIME\u7c7b\u578b\u7684\u7ec4\u5408\uff0c\u53ef\u4ee5\u8868\u793a\u4e3a YYYY-MM-DD HH:MM:SS<\/p>\n\n\n\n
           \u4ee5Y YYY-MM-DD HH:MM:SS \u683c\u5f0f\u6216\u8005 YYYYMMDDHHMMSS \u683c\u5f0f\u7684\u5b57\u7b26\u4e32\u63d2\u5165DATETIME\u7c7b\u578b\u7684\u5b57\u6bb5\u65f6\uff0c \u6700\u5c0f\u503c\u4e3a1000-01-01 00:00:00\uff0c\u6700\u5927\u503c\u4e3a9999-12-03 23:59:59\u3002 \u4ee5YYYYMMDDHHMMSS\u683c\u5f0f\u7684\u6570\u5b57\u63d2\u5165DATETIME\u7c7b\u578b\u7684\u5b57\u6bb5\u65f6\uff0c\u4f1a\u88ab\u8f6c\u5316\u4e3aYYYY-MM-DD HH:MM:SS\u683c\u5f0f\u3002 \u4ee5Y Y-MM-DD HH:MM:SS \u683c\u5f0f\u6216\u8005 YYMMDDHHMMSS \u683c\u5f0f\u7684\u5b57\u7b26\u4e32\u63d2\u5165DATETIME\u7c7b\u578b\u7684\u5b57\u6bb5\u65f6\uff0c\u4e24\u4f4d \u6570\u7684\u5e74\u4efd\u89c4\u5219\u7b26\u5408YEAR\u7c7b\u578b\u7684\u89c4\u5219\uff0c00\u523069\u8868\u793a2000\u52302069\uff1b70\u523099\u8868\u793a1970\u52301999\u3002 \u4f7f\u7528\u51fd\u6570 CURRENT_TIMESTAMP() \u548c NOW() \uff0c\u53ef\u4ee5\u5411DATETIME\u7c7b\u578b\u7684\u5b57\u6bb5\u63d2\u5165\u7cfb\u7edf\u7684\u5f53\u524d\u65e5\u671f\u548c \u65f6\u95f4\u3002<\/p>\n\n\n\n
          #6.4 DATETIME\u7c7b\u578b\nCREATE TABLE test_datetime1(\ndt DATETIME\n);\n\nINSERT INTO test_datetime1\nVALUES ('2021-01-01 06:50:30'), ('20210101065030');\n\nINSERT INTO test_datetime1\nVALUES ('99-01-01 00:00:00'), ('990101000000'), ('20-01-01 00:00:00'), ('200101000000');\n\nINSERT INTO test_datetime1\nVALUES (20200101000000), (200101000000), (19990101000000), (990101000000);\n \nINSERT INTO test_datetime1\nVALUES (CURRENT_TIMESTAMP()), (NOW()),(SYSDATE());\n\nSELECT *\nFROM test_datetime1;<\/code><\/pre>\n\n\n\n
           6.5 TIMESTAMP\u7c7b\u578b<\/h3>\n\n\n\n
          TIMESTAMP\u7c7b\u578b\u4e5f\u53ef\u4ee5\u8868\u793a\u65e5\u671f\u65f6\u95f4\uff0c\u5176\u663e\u793a\u683c\u5f0f\u4e0eDATETIME\u7c7b\u578b\u76f8\u540c\uff0c\u90fd\u662f YYYY-MM-DD HH:MM:SS \uff0c\u9700\u89814\u4e2a\u5b57\u8282\u7684\u5b58\u50a8\u7a7a\u95f4\u3002\u4f46\u662fTIMESTAMP\u5b58\u50a8\u7684\u65f6\u95f4\u8303\u56f4\u6bd4DATETIME\u8981\u5c0f\u5f88\u591a\uff0c\u53ea\u80fd\u5b58\u50a8 \u201c1970-01-01 00:00:01 UTC\u201d\u5230\u201c2038-01-19 03:14:07 UTC\u201d\u4e4b\u95f4\u7684\u65f6\u95f4\u3002\u5176\u4e2d\uff0cUTC\u8868\u793a\u4e16\u754c\u7edf\u4e00\u65f6\u95f4\uff0c\u4e5f\u53eb \u4f5c\u4e16\u754c\u6807\u51c6\u65f6\u95f4\u3002<\/p>\n\n\n\n
          \u5b58\u50a8\u6570\u636e\u7684\u65f6\u5019\u9700\u8981\u5bf9\u5f53\u524d\u65f6\u95f4\u6240\u5728\u7684\u65f6\u533a\u8fdb\u884c\u8f6c\u6362\uff0c\u67e5\u8be2\u6570\u636e\u7684\u65f6\u5019\u518d\u5c06\u65f6\u95f4\u8f6c\u6362\u56de\u5f53\u524d\u7684\u65f6 \u533a\u3002\u56e0\u6b64\uff0c\u4f7f\u7528TIMESTAMP\u5b58\u50a8\u7684\u540c\u4e00\u4e2a\u65f6\u95f4\u503c\uff0c\u5728\u4e0d\u540c\u7684\u65f6\u533a\u67e5\u8be2\u65f6\u4f1a\u663e\u793a\u4e0d\u540c\u7684\u65f6\u95f4\u3002<\/strong><\/p>\n\n\n\n
          \u5411TIMESTAMP\u7c7b\u578b\u7684\u5b57\u6bb5\u63d2\u5165\u6570\u636e\u65f6\uff0c\u5f53\u63d2\u5165\u7684\u6570\u636e\u683c\u5f0f\u6ee1\u8db3YY-MM-DD HH:MM:SS\u548cYYMMDDHHMMSS \u65f6\uff0c\u4e24\u4f4d\u6570\u503c\u7684\u5e74\u4efd\u540c\u6837\u7b26\u5408YEAR\u7c7b\u578b\u7684\u89c4\u5219\u6761\u4ef6\uff0c\u53ea\u4e0d\u8fc7\u8868\u793a\u7684\u65f6\u95f4\u8303\u56f4\u8981\u5c0f\u5f88\u591a\u3002
          \u5982\u679c\u5411TIMESTAMP\u7c7b\u578b\u7684\u5b57\u6bb5\u63d2\u5165\u7684\u65f6\u95f4\u8d85\u51fa\u4e86TIMESTAMP\u7c7b\u578b\u7684\u8303\u56f4\uff0c\u5219MySQL\u4f1a\u629b\u51fa\u9519\u8bef\u4fe1\u606f\u3002<\/p>\n\n\n\n
          #6.5 TIMESTAMP\u7c7b\u578b\nCREATE TABLE test_timestamp1(\nts TIMESTAMP\n);\n\nINSERT INTO test_timestamp1\nVALUES ('1999-01-01 03:04:50'), ('19990101030405'), ('99-01-01 03:04:05'), ('990101030405');\n\nINSERT INTO test_timestamp1\nVALUES ('2020@01@01@00@00@00'), ('20@01@01@00@00@00');\n\nINSERT INTO test_timestamp1\nVALUES (CURRENT_TIMESTAMP()), (NOW());\n\n#Incorrect datetime value\nINSERT INTO test_timestamp1\nVALUES ('2038-01-20 03:14:07');\n\nSELECT *\nFROM test_timestamp1;\n\n#\u5bf9\u6bd4DATETIME \u548c TIMESTAMP\nCREATE TABLE temp_time(\nd1 DATETIME,\nd2 TIMESTAMP\n);\n\nINSERT INTO temp_time VALUES('2021-9-2 14:45:52','2021-9-2 14:45:52');\n\nINSERT INTO temp_time VALUES(NOW(),NOW());\n\nSELECT * FROM temp_time;\n\n#\u4fee\u6539\u5f53\u524d\u7684\u65f6\u533a\nSET time_zone = '+9:00';\n\nSELECT * FROM temp_time;<\/code><\/pre>\n\n\n\n
          \u7528\u5f97\u6700\u591a\u7684\u65e5\u671f\u65f6\u95f4\u7c7b\u578b\uff0c\u5c31\u662f DATETIME <\/strong>\u3002\u867d\u7136 MySQL \u4e5f\u652f\u6301 YEAR\uff08\u5e74\uff09\u3001 TIME\uff08\u65f6\u95f4\uff09\u3001 DATE\uff08\u65e5\u671f\uff09\uff0c\u4ee5\u53ca TIMESTAMP \u7c7b\u578b\uff0c\u4f46\u662f\u5728\u5b9e\u9645\u9879\u76ee\u4e2d\uff0c\u5c3d\u91cf\u7528 DATETIME \u7c7b\u578b\u3002\u56e0\u4e3a\u8fd9\u4e2a\u6570\u636e\u7c7b\u578b \u5305\u62ec\u4e86\u5b8c\u6574\u7684\u65e5\u671f\u548c\u65f6\u95f4\u4fe1\u606f\uff0c\u53d6\u503c\u8303\u56f4\u4e5f\u6700\u5927\uff0c\u4f7f\u7528\u8d77\u6765\u6bd4\u8f83\u65b9\u4fbf\u3002\u6bd5\u7adf\uff0c\u5982\u679c\u65e5\u671f\u65f6\u95f4\u4fe1\u606f\u5206\u6563\u5728 \u597d\u51e0\u4e2a\u5b57\u6bb5\uff0c\u5f88\u4e0d\u5bb9\u6613\u8bb0\uff0c\u800c\u4e14\u67e5\u8be2\u7684\u65f6\u5019\uff0cSQL \u8bed\u53e5\u4e5f\u4f1a\u66f4\u52a0\u590d\u6742\u3002 \u6b64\u5916\uff0c\u4e00\u822c\u5b58\u6ce8\u518c\u65f6\u95f4\u3001\u5546\u54c1\u53d1\u5e03\u65f6\u95f4\u7b49\uff0c\u4e0d\u5efa\u8bae\u4f7f\u7528DATETIME\u5b58\u50a8\uff0c\u800c\u662f\u4f7f\u7528 \u65f6\u95f4\u6233<\/strong>\uff0c\u56e0\u4e3a DATETIME\u867d\u7136\u76f4\u89c2\uff0c\u4f46\u4e0d\u4fbf\u4e8e\u8ba1\u7b97\u3002<\/p>\n\n\n\n
           7. \u6587\u672c\u5b57\u7b26\u4e32\u7c7b\u578b<\/h2>\n\n\n\n
          \u6587\u672c\u5b57\u7b26\u4e32\u7c7b\u578b<\/th>\u503c\u7684\u957f\u5ea6<\/th>\u957f\u5ea6\u8303\u56f4<\/th>\u5360\u7528\u7684\u5b58\u50a8\u7a7a\u95f4<\/th><\/tr><\/thead>
          CHAR(M)<\/td>M<\/td>0 <= M <= 255<\/td>M\u4e2a\u5b57\u8282<\/td><\/tr>
          VARCHAR(M)<\/td>M<\/td>0 <= M <= 65535<\/td>M+1\u4e2a\u5b57\u8282<\/td><\/tr>
          TINYTEXT<\/td>L<\/td>0 <= L <= 255<\/td>L+2\u4e2a\u5b57\u8282<\/td><\/tr>
          TEXT<\/td>L<\/td>0 <= L <= 65535<\/td>L+2\u4e2a\u5b57\u8282<\/td><\/tr>
          MEDIUMTEXT<\/td>L<\/td>0 <= L <= 16777215<\/td>L+3\u4e2a\u5b57\u8282<\/td><\/tr>
          LONGTEXT<\/td>L<\/td>0 <= L <= 4294967295<\/td>L+4\u4e2a\u5b57\u8282<\/td><\/tr>
          ENUM<\/td>L<\/td>1 <= L <= 65535<\/td>1\u62162\u4e2a\u5b57\u8282<\/td><\/tr>
          SET<\/td>L<\/td>0 <= L <= 64<\/td>1,2,3,4\u62168\u4e2a\u5b57\u8282<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
          #7.1 CHAR\u7c7b\u578b\nCREATE TABLE test_char1(\nc1 CHAR,\nc2 CHAR(5)\n);\n\nDESC test_char1;\n\nINSERT INTO test_char1(c1)\nVALUES('a');\n\n#Data too long for column 'c1' at row 1\nINSERT INTO test_char1(c1)\nVALUES('ab');\n\nINSERT INTO test_char1(c2)\nVALUES('ab');\n\nINSERT INTO test_char1(c2)\nVALUES('hello');\n\nINSERT INTO test_char1(c2)\nVALUES('\u5c1a');\n\nINSERT INTO test_char1(c2)\nVALUES('\u7845\u8c37');\n\nINSERT INTO test_char1(c2)\nVALUES('\u5c1a\u7845\u8c37\u6559\u80b2');\n\n#Data too long for column 'c2' at row 1\nINSERT INTO test_char1(c2)\nVALUES('\u5c1a\u7845\u8c37IT\u6559\u80b2');\n\nSELECT * FROM test_char1;<\/code><\/pre>\n\n\n\n
            \n
          1. CHAR(M) \u7c7b\u578b\u4e00\u822c\u9700\u8981\u9884\u5148\u5b9a\u4e49\u5b57\u7b26\u4e32\u957f\u5ea6\u3002\u5982\u679c\u4e0d\u6307\u5b9a(M)\uff0c\u5219\u8868\u793a\u957f\u5ea6\u9ed8\u8ba4\u662f1\u4e2a\u5b57\u7b26\u3002<\/li>\n\n\n\n
          2. \u5982\u679c\u4fdd\u5b58\u65f6\uff0c\u6570\u636e\u7684\u5b9e\u9645\u957f\u5ea6\u6bd4CHAR\u7c7b\u578b\u58f0\u660e\u7684\u957f\u5ea6\u5c0f\uff0c\u5219\u4f1a\u5728 \u53f3\u4fa7\u586b\u5145\u7a7a\u683c\u4ee5\u8fbe\u5230\u6307\u5b9a\u7684\u957f \u5ea6\u3002\u5f53MySQL\u68c0\u7d22CHAR\u7c7b\u578b\u7684\u6570\u636e\u65f6\uff0cCHAR\u7c7b\u578b\u7684\u5b57\u6bb5\u4f1a\u53bb\u9664\u5c3e\u90e8\u7684\u7a7a\u683c\u3002<\/li>\n\n\n\n
          3. \u5b9a\u4e49CHAR\u7c7b\u578b\u5b57\u6bb5\u65f6\uff0c\u58f0\u660e\u7684\u5b57\u6bb5\u957f\u5ea6\u5373\u4e3aCHAR\u7c7b\u578b\u5b57\u6bb5\u6240\u5360\u7684\u5b58\u50a8\u7a7a\u95f4\u7684\u5b57\u8282\u6570\u3002<\/li>\n<\/ol>\n\n\n\n
             \u8fd9\u91cc\u7684char\uff08n\uff09\u8868\u793a\u7684\u662f\u5b57\u8282\uff01\uff01\uff01\uff01\uff01\uff01\u867d\u7136\u80fd\u5b58\u50a8n\u4e2a\u6c49\u5b57\uff0c\u5e95\u5c42\u53ea\u662f\u622a\u53d6\u4e86\uff0c\u8fd8\u662fn\u4e2a\u5b57\u8282\u6765\u5b58\u50a8\u7684<\/p>\n\n\n\n
              \n
            1. VARCHAR(M) \u5b9a\u4e49\u65f6\uff0c \u5fc5\u987b\u6307\u5b9a\u957f\u5ea6M\uff0c\u5426\u5219\u62a5\u9519\u3002<\/li>\n\n\n\n
            2. MySQL4.0\u7248\u672c\u4ee5\u4e0b\uff0cvarchar(20)\uff1a\u6307\u7684\u662f20\u5b57\u8282\uff0c\u5982\u679c\u5b58\u653eUTF8\u6c49\u5b57\u65f6\uff0c\u53ea\u80fd\u5b586\u4e2a\uff08\u6bcf\u4e2a\u6c49\u5b573\u5b57 \u8282\uff09 \uff1bMySQL5.0\u7248\u672c\u4ee5\u4e0a\uff0cvarchar(20)\uff1a\u6307\u7684\u662f20\u5b57\u7b26\u3002<\/li>\n\n\n\n
            3. \u68c0\u7d22VARCHAR\u7c7b\u578b\u7684\u5b57\u6bb5\u6570\u636e\u65f6\uff0c\u4f1a\u4fdd\u7559\u6570\u636e\u5c3e\u90e8\u7684\u7a7a\u683c\u3002VARCHAR\u7c7b\u578b\u7684\u5b57\u6bb5\u6240\u5360\u7528\u7684\u5b58\u50a8\u7a7a\u95f4 \u4e3a\u5b57\u7b26\u4e32\u5b9e\u9645\u957f\u5ea6\u52a01\u4e2a\u5b57\u8282\u3002\u00a0<\/li>\n<\/ol>\n\n\n\n
              #7.2 VARCHAR\u7c7b\u578b\nCREATE TABLE test_varchar1(\nNAME VARCHAR  #\u9519\u8bef\n);\n\n#Column length too big for column 'name' (max = 21845); use BLOB or TEXT instead\nCREATE TABLE test_varchar2(\nNAME VARCHAR(65535)\n);\n#\u8fd9\u91cc21845*3=65535\u4e86\uff0c\u4f46\u662f\u4e00\u4e2a\u6c49\u5b57\u4e09\u4e2a\u5b57\u8282\uff0c\n\n\nCREATE TABLE test_varchar3(\nNAME VARCHAR(5)\n);\n\nINSERT INTO test_varchar3\nVALUES('\u5c1a\u7845\u8c37'),('\u5c1a\u7845\u8c37\u6559\u80b2');\n\n#Data too long for column 'NAME' at row 1\nINSERT INTO test_varchar3\nVALUES('\u5c1a\u7845\u8c37IT\u6559\u80b2');<\/code><\/pre>\n\n\n\n
              \u54ea\u4e9b\u60c5\u51b5\u4f7f\u7528 CHAR \u6216 VARCHAR \u66f4\u597d<\/p>\n\n\n\n
              | \u7c7b\u578b       | \u7279\u70b9     | \u7a7a\u95f4\u4e0a         | \u65f6\u95f4\u4e0a   | \u9002\u7528\u573a\u666f         |
              |------------|----------|----------------|----------|------------------|
              | CHAR(M)    | \u56fa\u5b9a\u957f\u5ea6 | \u6d6a\u8d39\u5b58\u50a8\u7a7a\u95f4   | \u6548\u7387\u9ad8   | \u5b58\u50a8\u4e0d\u5927\uff0c\u901f\u5ea6\u8981\u6c42\u9ad8 |
              | VARCHAR(M) | \u53ef\u53d8\u957f\u5ea6 | \u8282\u7701\u5b58\u50a8\u7a7a\u95f4   | \u6548\u7387\u4f4e   | \u975eCHAR\u7684\u60c5\u51b5     |<\/p>\n\n\n\n
              \u60c5\u51b51\uff1a\u5b58\u50a8\u5f88\u77ed\u7684\u4fe1\u606f\u3002\u6bd4\u5982\u95e8\u724c\u53f7\u7801101\uff0c201\u2026\u2026\u8fd9\u6837\u5f88\u77ed\u7684\u4fe1\u606f\u5e94\u8be5\u7528char\uff0c\u56e0\u4e3avarchar\u8fd8\u8981\u5360\u4e2abyte\u7528\u4e8e\u5b58\u50a8\u4fe1\u606f\u957f\u5ea6\uff0c\u672c\u6765\u6253\u7b97\u8282\u7ea6\u5b58\u50a8\u7684\uff0c\u7ed3\u679c\u5f97\u4e0d\u507f\u5931\u3002<\/p>\n\n\n\n
              \u60c5\u51b52\uff1a\u56fa\u5b9a\u957f\u5ea6\u7684\u3002\u6bd4\u5982\u4f7f\u7528uuid\u4f5c\u4e3a\u4e3b\u952e\uff0c\u90a3\u7528char\u5e94\u8be5\u66f4\u5408\u9002\u3002\u56e0\u4e3a\u4ed6\u56fa\u5b9a\u957f\u5ea6\uff0cvarchar\u52a8\u6001\u6839\u636e\u957f\u5ea6\u7684\u7279\u6027\u5c31\u6d88\u5931\u4e86\uff0c\u800c\u4e14\u8fd8\u8981\u5360\u4e2a\u957f\u5ea6\u4fe1\u606f\u3002<\/p>\n\n\n\n
              \u60c5\u51b53\uff1a\u5341\u5206\u9891\u7e41\u6539\u53d8\u7684column\u3002\u56e0\u4e3avarchar\u6bcf\u6b21\u5b58\u50a8\u90fd\u8981\u6709\u989d\u5916\u7684\u8ba1\u7b97\uff0c\u5f97\u5230\u957f\u5ea6\u7b49\u5de5\u4f5c\uff0c\u5982\u679c\u4e00\u4e2a\u975e\u5e38\u9891\u7e41\u6539\u53d8\u7684\uff0c\u90a3\u5c31\u8981\u6709\u5f88\u591a\u7684\u7cbe\u529b\u7528\u4e8e\u8ba1\u7b97\uff0c\u800c\u8fd9\u4e9b\u5bf9\u4e8echar\u6765\u8bf4\u662f\u4e0d\u9700\u8981\u7684\u3002<\/p>\n\n\n\n
              \u60c5\u51b54\uff1a\u5177\u4f53\u5b58\u50a8\u5f15\u64ce\u4e2d\u7684\u60c5\u51b5\uff1a
              - MyISAM \u6570\u636e\u5b58\u50a8\u5f15\u64ce\u548c\u6570\u636e\u5217\uff1aMyISAM\u6570\u636e\u8868\uff0c\u6700\u597d\u4f7f\u7528\u56fa\u5b9a\u957f\u5ea6\uff08CHAR\uff09\u7684\u6570\u636e\u5217\u4ee3\u66ff\u53ef\u53d8\u957f\u5ea6\uff08VARCHAR\uff09\u7684\u6570\u636e\u5217\u3002\u8fd9\u6837\u4f7f\u5f97\u6574\u4e2a\u8868\u9759\u6001\u5316\uff0c\u4ece\u800c\u4f7f\u6570\u636e\u68c0\u7d22\u66f4\u5feb\uff0c\u7528\u7a7a\u95f4\u6362\u65f6\u95f4\u3002
              - MEMORY \u5b58\u50a8\u5f15\u64ce\u548c\u6570\u636e\u5217\uff1aMEMORY\u6570\u636e\u8868\u76ee\u524d\u90fd\u4f7f\u7528\u56fa\u5b9a\u957f\u5ea6\u7684\u6570\u636e\u884c\u5b58\u50a8\uff0c\u56e0\u6b64\u65e0\u8bba\u4f7f\u7528CHAR\u6216VARCHAR\u90fd\u6ca1\u6709\u5173\u7cfb\uff0c\u4e24\u8005\u90fd\u662f\u4f5c\u4e3aCHAR\u7c7b\u578b\u5904\u7406\u7684\u3002
              - InnoDB \u5b58\u50a8\u5f15\u64ce\uff0c\u5efa\u8bae\u4f7f\u7528VARCHAR\u7c7b\u578b\u3002\u56e0\u4e3a\u5bf9\u4e8eInnoDB\u6570\u636e\u8868\uff0c\u5185\u90e8\u7684\u884c\u5b58\u50a8\u683c\u5f0f\u5e76\u6ca1\u6709\u533a\u5206\u56fa\u5b9a\u957f\u5ea6\u548c\u53ef\u53d8\u957f\u5ea6\u5217\uff08\u6240\u6709\u6570\u636e\u884c\u90fd\u4f7f\u7528\u6307\u5411\u6570\u636e\u5217\u503c\u7684\u5934\u6307\u9488\uff09\uff0c\u800c\u4e14\u4e3b\u8981\u5f71\u54cd\u6027\u80fd\u7684\u56e0\u7d20\u662f\u6570\u636e\u884c\u4f7f\u7528\u7684\u5b58\u50a8\u603b\u91cf<\/strong>\uff0c\u7531\u4e8echar\u5e73\u5747\u5360\u7528\u7684\u7a7a\u95f4\u591a\u4e8evarchar\uff0c\u6240\u4ee5\u9664\u4e86\u7b80\u77ed\u5e76\u4e14\u56fa\u5b9a\u957f\u5ea6\u7684\uff0c\u5176\u4ed6\u8003\u8651varchar\u3002\u8fd9\u6837\u8282\u7701\u7a7a\u95f4\uff0c\u5bf9\u78c1\u76d8I\/O\u548c\u6570\u636e\u5b58\u50a8\u603b\u91cf\u6bd4\u8f83\u597d\u3002<\/p>\n\n\n\n
              7.2 TEXT\u7c7b\u578b<\/h3>\n\n\n\n
              \u5728MySQL\u4e2d\uff0cTEXT\u7528\u6765\u4fdd\u5b58\u6587\u672c\u7c7b\u578b\u7684\u5b57\u7b26\u4e32\uff0c\u603b\u5171\u5305\u542b4\u79cd\u7c7b\u578b\uff0c\u5206\u522b\u4e3aTINYTEXT\u3001TEXT\u3001 MEDIUMTEXT \u548c LONGTEXT \u7c7b\u578b\u3002 \u5728\u5411TEXT\u7c7b\u578b\u7684\u5b57\u6bb5\u4fdd\u5b58\u548c\u67e5\u8be2\u6570\u636e\u65f6\uff0c\u7cfb\u7edf\u81ea\u52a8\u6309\u7167\u5b9e\u9645\u957f\u5ea6\u5b58\u50a8\uff0c\u4e0d\u9700\u8981\u9884\u5148\u5b9a\u4e49\u957f\u5ea6\u3002\u8fd9\u4e00\u70b9\u548c VARCHAR\u7c7b\u578b\u76f8\u540c\u3002\"\"<\/p>\n\n\n\n
              #7.3 TEXT\u7c7b\u578b\nCREATE TABLE test_text(\ntx TEXT\n);\n\nINSERT INTO test_text\nVALUES('atguigu   ');\n\nSELECT CHAR_LENGTH(tx)\nFROM test_text; #10\n\n#\u8bf4\u660e\u5728\u4fdd\u5b58\u548c\u67e5\u8be2\u6570\u636e\u65f6\uff0c\u5e76\u6ca1\u6709\u5220\u9664TEXT\u7c7b\u578b\u7684\u6570\u636e\u5c3e\u90e8\u7684\u7a7a\u683c\u3002<\/code><\/pre>\n\n\n\n
               \u7531\u4e8e\u5b9e\u9645\u5b58\u50a8\u7684\u957f\u5ea6\u4e0d\u786e\u5b9a\uff0cMySQL \u4e0d\u5141\u8bb8 TEXT \u7c7b\u578b\u7684\u5b57\u6bb5\u505a\u4e3b\u952e\u3002\u9047\u5230\u8fd9\u79cd\u60c5\u51b5\uff0c\u4f60\u53ea\u80fd\u91c7\u7528 CHAR(M)\uff0c\u6216\u8005 VARCHAR(M)\u3002<\/p>\n\n\n\n
              \u5f00\u53d1\u4e2d\u7ecf\u9a8c\uff1a TEXT\u6587\u672c\u7c7b\u578b\uff0c\u53ef\u4ee5\u5b58\u6bd4\u8f83\u5927\u7684\u6587\u672c\u6bb5\uff0c\u641c\u7d22\u901f\u5ea6\u7a0d\u6162\uff0c\u56e0\u6b64\u5982\u679c\u4e0d\u662f\u7279\u522b\u5927\u7684\u5185\u5bb9\uff0c\u5efa\u8bae\u4f7f\u7528CHAR\uff0c VARCHAR\u6765\u4ee3\u66ff\u3002\u8fd8\u6709TEXT\u7c7b\u578b\u4e0d\u7528\u52a0\u9ed8\u8ba4\u503c\uff0c\u52a0\u4e86\u4e5f\u6ca1\u7528\u3002\u800c\u4e14text\u548cblob\u7c7b\u578b\u7684\u6570\u636e\u5220\u9664\u540e\u5bb9\u6613\u5bfc\u81f4 \u201c\u7a7a\u6d1e\u201d\uff0c\u4f7f\u5f97\u6587\u4ef6\u788e\u7247\u6bd4\u8f83\u591a\uff0c\u6240\u4ee5\u9891\u7e41\u4f7f\u7528\u7684\u8868\u4e0d\u5efa\u8bae\u5305\u542bTEXT\u7c7b\u578b\u5b57\u6bb5\uff0c\u5efa\u8bae\u5355\u72ec\u5206\u51fa\u53bb\uff0c\u5355\u72ec\u7528 \u4e00\u4e2a\u8868\u3002<\/p>\n\n\n\n
              8. ENUM\u7c7b\u578b<\/h2>\n\n\n\n
              ENUM\u7c7b\u578b\u4e5f\u53eb\u4f5c\u679a\u4e3e\u7c7b\u578b\uff0cENUM\u7c7b\u578b\u7684\u53d6\u503c\u8303\u56f4\u9700\u8981\u5728\u5b9a\u4e49\u5b57\u6bb5\u65f6\u8fdb\u884c\u6307\u5b9a\u3002\u8bbe\u7f6e\u5b57\u6bb5\u503c\u65f6\uff0cENUM \u7c7b\u578b\u53ea\u5141\u8bb8\u4ece\u6210\u5458\u4e2d\u9009\u53d6\u5355\u4e2a\u503c\uff0c\u4e0d\u80fd\u4e00\u6b21\u9009\u53d6\u591a\u4e2a\u503c\u3002 \u5176\u6240\u9700\u8981\u7684\u5b58\u50a8\u7a7a\u95f4\u7531\u5b9a\u4e49ENUM\u7c7b\u578b\u65f6\u6307\u5b9a\u7684\u6210\u5458\u4e2a\u6570\u51b3\u5b9a\u3002\u00a0\"\"<\/p>\n\n\n\n
              #8. ENUM\u7c7b\u578b\n\nCREATE TABLE test_enum(\nseason ENUM('\u6625','\u590f','\u79cb','\u51ac','unknow')\n);\n\nINSERT INTO test_enum\nVALUES('\u6625'),('\u79cb');\n\nSELECT * FROM test_enum;\n\n#Data truncated for column 'season' at row 1\nINSERT INTO test_enum\nVALUES('\u6625,\u79cb');\n#Data truncated for column 'season' at row 1\nINSERT INTO test_enum\nVALUES('\u4eba');\n\nINSERT INTO test_enum\nVALUES('unknow');\n\n#\u5ffd\u7565\u5927\u5c0f\u5199\u7684\nINSERT INTO test_enum\nVALUES('UNKNOW');\n\n#\u53ef\u4ee5\u4f7f\u7528\u7d22\u5f15\u8fdb\u884c\u679a\u4e3e\u5143\u7d20\u7684\u8c03\u7528\nINSERT INTO test_enum\nVALUES(1),('3');\n\n# \u6ca1\u6709\u9650\u5236\u975e\u7a7a\u7684\u60c5\u51b5\u4e0b\uff0c\u53ef\u4ee5\u6dfb\u52a0null\u503c\nINSERT INTO test_enum\nVALUES (NULL);<\/code><\/pre>\n\n\n\n
              9. SET\u7c7b\u578b<\/h2>\n\n\n\n
              SET\u8868\u793a\u4e00\u4e2a\u5b57\u7b26\u4e32\u5bf9\u8c61\uff0c\u53ef\u4ee5\u5305\u542b0\u4e2a\u6216\u591a\u4e2a\u6210\u5458\uff0c\u4f46\u6210\u5458\u4e2a\u6570\u7684\u4e0a\u9650\u4e3a 64 \u3002\u8bbe\u7f6e\u5b57\u6bb5\u503c\u65f6\uff0c\u53ef\u4ee5\u53d6 \u53d6\u503c\u8303\u56f4\u5185\u7684 0 \u4e2a\u6216\u591a\u4e2a\u503c\u3002 \u5f53SET\u7c7b\u578b\u5305\u542b\u7684\u6210\u5458\u4e2a\u6570\u4e0d\u540c\u65f6\uff0c\u5176\u6240\u5360\u7528\u7684\u5b58\u50a8\u7a7a\u95f4\u4e5f\u662f\u4e0d\u540c\u7684\uff0c\u5177\u4f53\u5982\u4e0b\uff1a<\/p>\n\n\n\n
              \u6210\u5458\u4e2a\u6570\u8303\u56f4\uff08L\u8868\u793a\u5b9e\u9645\u6210\u5458\u4e2a\u6570\uff09<\/th>\u5360\u7528\u7684\u5b58\u50a8\u7a7a\u95f4<\/th><\/tr><\/thead>
              1 <= L <= 8<\/td>1\u4e2a\u5b57\u8282<\/td><\/tr>
              9 <= L <= 16<\/td>2\u4e2a\u5b57\u8282<\/td><\/tr>
              17 <= L <= 24<\/td>3\u4e2a\u5b57\u8282<\/td><\/tr>
              25 <= L <= 32<\/td>4\u4e2a\u5b57\u8282<\/td><\/tr>
              33 <= L <= 64<\/td>8\u4e2a\u5b57\u8282<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
              SET\u7c7b\u578b\u5728\u5b58\u50a8\u6570\u636e\u65f6\u6210\u5458\u4e2a\u6570\u8d8a\u591a\uff0c\u5176\u5360\u7528\u7684\u5b58\u50a8\u7a7a\u95f4\u8d8a\u5927\u3002\u6ce8\u610f\uff1aSET\u7c7b\u578b\u5728\u9009\u53d6\u6210\u5458\u65f6\uff0c\u53ef\u4ee5\u4e00\u6b21 \u9009\u62e9\u591a\u4e2a\u6210\u5458\uff0c\u8fd9\u4e00\u70b9\u4e0eENUM\u7c7b\u578b\u4e0d\u540c\u3002<\/p>\n\n\n\n
              #9. SET\u7c7b\u578b\nCREATE TABLE test_set(\ns SET ('A', 'B', 'C')\n);\n\nINSERT INTO test_set (s) VALUES ('A'), ('A,B');\n\n#\u63d2\u5165\u91cd\u590d\u7684SET\u7c7b\u578b\u6210\u5458\u65f6\uff0cMySQL\u4f1a\u81ea\u52a8\u5220\u9664\u91cd\u590d\u7684\u6210\u5458\nINSERT INTO test_set (s) VALUES ('A,B,C,A');\n\n#\u5411SET\u7c7b\u578b\u7684\u5b57\u6bb5\u63d2\u5165SET\u6210\u5458\u4e2d\u4e0d\u5b58\u5728\u7684\u503c\u65f6\uff0cMySQL\u4f1a\u629b\u51fa\u9519\u8bef\u3002\nINSERT INTO test_set (s) VALUES ('A,B,C,D');\n\nSELECT *\nFROM test_set;\n\n\nCREATE TABLE temp_mul(\ngender ENUM('\u7537','\u5973'),\nhobby SET('\u5403\u996d','\u7761\u89c9','\u6253\u8c46\u8c46','\u5199\u4ee3\u7801')\n);\n\nINSERT INTO temp_mul\nVALUES('\u7537','\u7761\u89c9,\u6253\u8c46\u8c46');\n\nSELECT * \nFROM temp_mul;\n\n#Data truncated for column 'gender' at row 1\nINSERT INTO temp_mul\nVALUES('\u7537,\u5973','\u7761\u89c9,\u6253\u8c46\u8c46');<\/code><\/pre>\n\n\n\n
              10. \u4e8c\u8fdb\u5236\u5b57\u7b26\u4e32\u7c7b\u578b<\/h2>\n\n\n\n
              MySQL\u4e2d\u7684\u4e8c\u8fdb\u5236\u5b57\u7b26\u4e32\u7c7b\u578b\u4e3b\u8981\u5b58\u50a8\u4e00\u4e9b\u4e8c\u8fdb\u5236\u6570\u636e\uff0c\u6bd4\u5982\u53ef\u4ee5\u5b58\u50a8\u56fe\u7247\u3001\u97f3\u9891\u548c\u89c6\u9891\u7b49\u4e8c\u8fdb\u5236\u6570\u636e\u3002<\/p>\n\n\n\n
               BINARY\u4e0eVARBINARY\u7c7b\u578b<\/h3>\n\n\n\n
              BINARY\u548cVARBINARY\u7c7b\u4f3c\u4e8eCHAR\u548cVARCHAR\uff0c\u53ea\u662f\u5b83\u4eec\u5b58\u50a8\u7684\u662f\u4e8c\u8fdb\u5236\u5b57\u7b26\u4e32\u3002\uff08char\u548cbinary\u7684\u533a\u522b\u662f\uff0cchar\uff081\uff09\u662f\u5b58\u50a8\u5b57\u7b26\uff0cbinary\uff081\uff09\u662f\u5b58\u50a8\u4e00\u4e2a\u5b57\u8282\uff09\"\"<\/p>\n\n\n\n
              BINARY (M)\u4e3a\u56fa\u5b9a\u957f\u5ea6\u7684\u4e8c\u8fdb\u5236\u5b57\u7b26\u4e32\uff0cM\u8868\u793a\u6700\u591a\u80fd\u5b58\u50a8\u7684\u5b57\u8282\u6570\uff0c\u53d6\u503c\u8303\u56f4\u662f0~255\u4e2a\u5b57\u7b26\u3002\u5982\u679c\u672a \u6307\u5b9a(M)\uff0c\u8868\u793a\u53ea\u80fd\u5b58\u50a8 1\u4e2a\u5b57\u8282\u3002\u4f8b\u5982BINARY (8)\uff0c\u8868\u793a\u6700\u591a\u80fd\u5b58\u50a88\u4e2a\u5b57\u8282\uff0c\u5982\u679c\u5b57\u6bb5\u503c\u4e0d\u8db3(M)\u4e2a\u5b57 \u8282\uff0c\u5c06\u5728\u53f3\u8fb9\u586b\u5145'\\0'\u4ee5\u8865\u9f50\u6307\u5b9a\u957f\u5ea6\u3002<\/p>\n\n\n\n
              VARBINARY (M)\u4e3a\u53ef\u53d8\u957f\u5ea6\u7684\u4e8c\u8fdb\u5236\u5b57\u7b26\u4e32\uff0cM\u8868\u793a\u6700\u591a\u80fd\u5b58\u50a8\u7684\u5b57\u8282\u6570\uff0c\u603b\u5b57\u8282\u6570\u4e0d\u80fd\u8d85\u8fc7\u884c\u7684\u5b57\u8282\u957f \u5ea6\u9650\u523665535\uff0c\u53e6\u5916\u8fd8\u8981\u8003\u8651\u989d\u5916\u5b57\u8282\u5f00\u9500\uff0cVARBINARY\u7c7b\u578b\u7684\u6570\u636e\u9664\u4e86\u5b58\u50a8\u6570\u636e\u672c\u8eab\u5916\uff0c\u8fd8\u9700\u89811\u62162\u4e2a \u5b57\u8282\u6765\u5b58\u50a8\u6570\u636e\u7684\u5b57\u8282\u6570\u3002VARBINARY\u7c7b\u578b \u5fc5\u987b\u6307\u5b9a(M) \uff0c\u5426\u5219\u62a5\u9519<\/p>\n\n\n\n
              #10.1 BINARY \u4e0e VARBINARY\u7c7b\u578b\nCREATE TABLE test_binary1(\nf1 BINARY,\nf2 BINARY(3),\n#f3 VARBINARY,\nf4 VARBINARY(10)\n);\n\nDESC test_binary1;\n\nINSERT INTO test_binary1(f1,f2)\nVALUES('a','abc');\n\nSELECT * FROM test_binary1;\n\n#Data too long for column 'f1' at row 1\nINSERT INTO test_binary1(f1)\nVALUES('ab');\n\nINSERT INTO test_binary1(f2,f4)\nVALUES('ab','ab');\n\nSELECT LENGTH(f2),LENGTH(f4)\nFROM test_binary1;<\/code><\/pre>\n\n\n\n
               BLOB\u7c7b\u578b<\/h3>\n\n\n\n
              BLOB\u662f\u4e00\u4e2a \u4e8c\u8fdb\u5236\u5927\u5bf9\u8c61\uff0c\u53ef\u4ee5\u5bb9\u7eb3\u53ef\u53d8\u6570\u91cf\u7684\u6570\u636e\u3002 MySQL\u4e2d\u7684BLOB\u7c7b\u578b\u5305\u62ecTINYBLOB\u3001BLOB\u3001MEDIUMBLOB\u548cLONGBLOB 4\u79cd\u7c7b\u578b\uff0c\u5b83\u4eec\u53ef\u5bb9\u7eb3\u503c\u7684\u6700\u5927 \u957f\u5ea6\u4e0d\u540c\u3002\u53ef\u4ee5\u5b58\u50a8\u4e00\u4e2a\u4e8c\u8fdb\u5236\u7684\u5927\u5bf9\u8c61\uff0c\u6bd4\u5982 \u56fe\u7247\u3001\u97f3\u9891\u548c \u89c6\u9891\u7b49\u3002<\/p>\n\n\n\n
              \u9700\u8981\u6ce8\u610f\u7684\u662f\uff0c\u5728\u5b9e\u9645\u5de5\u4f5c\u4e2d\uff0c\u5f80\u5f80\u4e0d\u4f1a\u5728MySQL\u6570\u636e\u5e93\u4e2d\u4f7f\u7528BLOB\u7c7b\u578b\u5b58\u50a8\u5927\u5bf9\u8c61\u6570\u636e\uff0c\u901a\u5e38\u4f1a\u5c06\u56fe \u7247\u3001\u97f3\u9891\u548c\u89c6\u9891\u6587\u4ef6\u5b58\u50a8\u5230 \u670d\u52a1\u5668\u7684\u78c1\u76d8\u4e0a\uff0c\u5e76\u5c06\u56fe\u7247\u3001\u97f3\u9891\u548c\u89c6\u9891\u7684\u8bbf\u95ee\u8def\u5f84\u5b58\u50a8\u5230MySQL\u4e2d\u3002\"\"<\/p>\n\n\n\n
              #10.2 Blob\u7c7b\u578b\nCREATE TABLE test_blob1(\nid INT,\nimg MEDIUMBLOB\n);\n\nINSERT INTO test_blob1(id)\nVALUES (1001);\n\nSELECT *\nFROM test_blob1;<\/code><\/pre>\n\n\n\n
              TEXT\u548cBLOB\u7684\u4f7f\u7528\u6ce8\u610f\u4e8b\u9879\uff1a \u5728\u4f7f\u7528text\u548cblob\u5b57\u6bb5\u7c7b\u578b\u65f6\u8981\u6ce8\u610f\u4ee5\u4e0b\u51e0\u70b9\uff0c\u4ee5\u4fbf\u66f4\u597d\u7684\u53d1\u6325\u6570\u636e\u5e93\u7684\u6027\u80fd\u3002<\/p>\n\n\n\n
                \n
              • \u2460 BLOB\u548cTEXT\u503c\u4e5f\u4f1a\u5f15\u8d77\u81ea\u5df1\u7684\u4e00\u4e9b\u95ee\u9898\uff0c\u7279\u522b\u662f\u6267\u884c\u4e86\u5927\u91cf\u7684\u5220\u9664\u6216\u66f4\u65b0\u64cd\u4f5c\u7684\u65f6\u5019\u3002\u5220\u9664\u8fd9\u79cd\u503c \u4f1a\u5728\u6570\u636e\u8868\u4e2d\u7559\u4e0b\u5f88\u5927\u7684\" \u7a7a\u6d1e\"\uff0c\u4ee5\u540e\u586b\u5165\u8fd9\u4e9b\"\u7a7a\u6d1e\"\u7684\u8bb0\u5f55\u53ef\u80fd\u957f\u5ea6\u4e0d\u540c\u3002\u4e3a\u4e86\u63d0\u9ad8\u6027\u80fd\uff0c\u5efa\u8bae\u5b9a\u671f \u4f7f\u7528 OPTIMIZE TABLE \u529f\u80fd\u5bf9\u8fd9\u7c7b\u8868\u8fdb\u884c \u788e\u7247\u6574\u7406\u3002<\/li>\n\n\n\n
              • \u2461 \u5982\u679c\u9700\u8981\u5bf9\u5927\u6587\u672c\u5b57\u6bb5\u8fdb\u884c\u6a21\u7cca\u67e5\u8be2\uff0cMySQL \u63d0\u4f9b\u4e86 \u524d\u7f00\u7d22\u5f15\u3002\u4f46\u662f\u4ecd\u7136\u8981\u5728\u4e0d\u5fc5\u8981\u7684\u65f6\u5019\u907f\u514d\u68c0 \u7d22\u5927\u578b\u7684BLOB\u6216TEXT\u503c\u3002\u4f8b\u5982\uff0cSELECT * \u67e5\u8be2\u5c31\u4e0d\u662f\u5f88\u597d\u7684\u60f3\u6cd5\uff0c\u9664\u975e\u4f60\u80fd\u591f\u786e\u5b9a\u4f5c\u4e3a\u7ea6\u675f\u6761\u4ef6\u7684 WHERE\u5b50\u53e5\u53ea\u4f1a\u627e\u5230\u6240\u9700\u8981\u7684\u6570\u636e\u884c\u3002\u5426\u5219\uff0c\u4f60\u53ef\u80fd\u6beb\u65e0\u76ee\u7684\u5730\u5728\u7f51\u7edc\u4e0a\u4f20\u8f93\u5927\u91cf\u7684\u503c\u3002<\/li>\n\n\n\n
              • \u2462 \u628aBLOB\u6216TEXT\u5217 \u5206\u79bb\u5230\u5355\u72ec\u7684\u8868\u4e2d\u3002\u5728\u67d0\u4e9b\u73af\u5883\u4e2d\uff0c\u5982\u679c\u628a\u8fd9\u4e9b\u6570\u636e\u5217\u79fb\u52a8\u5230\u7b2c\u4e8c\u5f20\u6570\u636e\u8868\u4e2d\uff0c\u53ef \u4ee5\u8ba9\u4f60\u628a\u539f\u6570\u636e\u8868\u4e2d\u7684\u6570\u636e\u5217\u8f6c\u6362\u4e3a\u56fa\u5b9a\u957f\u5ea6\u7684\u6570\u636e\u884c\u683c\u5f0f\uff0c\u90a3\u4e48\u5b83\u5c31\u662f\u6709\u610f\u4e49\u7684\u3002\u8fd9\u4f1a \u51cf\u5c11\u4e3b\u8868\u4e2d\u7684 \u788e\u7247\uff0c\u4f7f\u4f60\u5f97\u5230\u56fa\u5b9a\u957f\u5ea6\u6570\u636e\u884c\u7684\u6027\u80fd\u4f18\u52bf\u3002\u5b83\u8fd8\u4f7f\u4f60\u5728\u4e3b\u6570\u636e\u8868\u4e0a\u8fd0\u884c SELECT * \u67e5\u8be2\u7684\u65f6\u5019\u4e0d\u4f1a\u901a\u8fc7 \u7f51\u7edc\u4f20\u8f93\u5927\u91cf\u7684BLOB\u6216TEXT\u503c\u3002<\/li>\n<\/ul>\n\n\n\n
                 11. JSON \u7c7b\u578b<\/h2>\n\n\n\n
                JSON\uff08JavaScript Object Notation\uff09\u662f\u4e00\u79cd\u8f7b\u91cf\u7ea7\u7684 \u6570\u636e\u4ea4\u6362\u683c\u5f0f\u3002\u7b80\u6d01\u548c\u6e05\u6670\u7684\u5c42\u6b21\u7ed3\u6784\u4f7f\u5f97 JSON \u6210 \u4e3a\u7406\u60f3\u7684\u6570\u636e\u4ea4\u6362\u8bed\u8a00\u3002\u5b83\u6613\u4e8e\u4eba\u9605\u8bfb\u548c\u7f16\u5199\uff0c\u540c\u65f6\u4e5f\u6613\u4e8e\u673a\u5668\u89e3\u6790\u548c\u751f\u6210\uff0c\u5e76\u6709\u6548\u5730\u63d0\u5347\u7f51\u7edc\u4f20\u8f93\u6548 \u7387\u3002JSON \u53ef\u4ee5\u5c06 JavaScript \u5bf9\u8c61\u4e2d\u8868\u793a\u7684\u4e00\u7ec4\u6570\u636e\u8f6c\u6362\u4e3a\u5b57\u7b26\u4e32\uff0c\u7136\u540e\u5c31\u53ef\u4ee5\u5728\u7f51\u7edc\u6216\u8005\u7a0b\u5e8f\u4e4b\u95f4\u8f7b \u677e\u5730\u4f20\u9012\u8fd9\u4e2a\u5b57\u7b26\u4e32\uff0c\u5e76\u5728\u9700\u8981\u7684\u65f6\u5019\u5c06\u5b83\u8fd8\u539f\u4e3a\u5404\u7f16\u7a0b\u8bed\u8a00\u6240\u652f\u6301\u7684\u6570\u636e\u683c\u5f0f\u3002<\/p>\n\n\n\n
                CREATE TABLE test_json(\njs json\n\n);\n\nINSERT INTO test_json (js) \nVALUES ('{\"name\":\"songhk\", \"age\":18, \"address\":{\"province\":\"beijing\", \"city\":\"beijing\"}}');\n\n\nSELECT * FROM test_json;\n\nSELECT js -> '$.name' AS NAME,js -> '$.age' AS age ,js -> '$.address.province' AS province, js -> '$.address.city' AS city\nFROM test_json;<\/code><\/pre>\n\n\n\n
                \"\"<\/p>\n","protected":false},"excerpt":{"rendered":"
                 \u7b2c12\u7ae0_MySQL\u6570\u636e\u7c7b\u578b\u7cbe\u8bb2 \u7b2c\u4e09\u7ae0\u5230\u7b2c10\u7ae0\u662fDDL\uff0c\u7b2c11\u7ae0\u662fDML\uff0c\u63a5\u4e0b\u6765\u5c31\u662fDCL\u4e86\uff0cTCL\u4e4b\u7c7b\u7684\u5427 \u7c7b\u578b …<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"emotion":"","emotion_color":"","title_style":"","license":"","footnotes":""},"categories":[2],"tags":[16],"class_list":["post-858","post","type-post","status-publish","format-standard","hentry","category-2","tag-sql"],"_links":{"self":[{"href":"https:\/\/eve2333.top\/index.php?rest_route=\/wp\/v2\/posts\/858","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/eve2333.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/eve2333.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/eve2333.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/eve2333.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=858"}],"version-history":[{"count":1,"href":"https:\/\/eve2333.top\/index.php?rest_route=\/wp\/v2\/posts\/858\/revisions"}],"predecessor-version":[{"id":859,"href":"https:\/\/eve2333.top\/index.php?rest_route=\/wp\/v2\/posts\/858\/revisions\/859"}],"wp:attachment":[{"href":"https:\/\/eve2333.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=858"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/eve2333.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=858"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/eve2333.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=858"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}