{"id":146,"date":"2017-04-07T08:32:46","date_gmt":"2017-04-07T00:32:46","guid":{"rendered":"http:\/\/www.jsjs.org\/?p=146"},"modified":"2017-04-07T08:32:46","modified_gmt":"2017-04-07T00:32:46","slug":"mysql%e4%b8%advarchar%e6%9c%80%e5%a4%a7%e9%95%bf%e5%ba%a6%e6%98%af%e5%a4%9a%e5%b0%91%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/blog.jsjs.org\/?p=146","title":{"rendered":"MySQL\u4e2dvarchar\u6700\u5927\u957f\u5ea6\u662f\u591a\u5c11\uff1f"},"content":{"rendered":"<h1 class=\"postTitle\"><\/h1>\n<div class=\"postBody\">\n<div id=\"cnblogs_post_body\">\n<p><strong>\u4e00. varchar\u5b58\u50a8\u89c4\u5219\uff1a<\/strong><\/p>\n<p>4.0\u7248\u672c\u4ee5\u4e0b\uff0cvarchar(20)\uff0c\u6307\u7684\u662f20<strong>\u5b57\u8282<\/strong>\uff0c\u5982\u679c\u5b58\u653eUTF8\u6c49\u5b57\u65f6\uff0c\u53ea\u80fd\u5b586\u4e2a\uff08\u6bcf\u4e2a\u6c49\u5b573\u5b57\u8282\uff09<br \/>\n5.0\u7248\u672c\u4ee5\u4e0a\uff0cvarchar(20)\uff0c\u6307\u7684\u662f20<strong>\u5b57\u7b26<\/strong>\uff0c\u65e0\u8bba\u5b58\u653e\u7684\u662f\u6570\u5b57\u3001\u5b57\u6bcd\u8fd8\u662fUTF8\u6c49\u5b57\uff08\u6bcf\u4e2a\u6c49\u5b573\u5b57\u8282\uff09\uff0c\u90fd\u53ef\u4ee5\u5b58\u653e20\u4e2a\uff0c\u6700\u5927\u5927\u5c0f\u662f65532\u5b57\u8282<br \/>\nMysql4\u4e2d\u6700\u5927\u4e5f\u4e0d\u8fc7\u662f20\u4e2a\u5b57\u8282,\u4f46\u662fMysql5\u6839\u636e\u7f16\u7801\u4e0d\u540c,\u5b58\u50a8\u5927\u5c0f\u4e5f\u4e0d\u540c\u3002<\/p>\n<p>&nbsp;<\/p>\n<p><strong>\u4e8c. varchar\u548cchar \u7684\u533a\u522b\uff1a<\/strong><\/p>\n<p>char\u662f\u4e00\u79cd\u56fa\u5b9a\u957f\u5ea6\u7684\u7c7b\u578b\uff0cvarchar\u5219\u662f\u4e00\u79cd\u53ef\u53d8\u957f\u5ea6\u7684\u7c7b\u578b\uff0c\u5b83\u4eec\u7684\u533a\u522b\u662f\uff1a char(M)\u7c7b\u578b\u7684\u6570\u636e\u5217\u91cc\uff0c\u6bcf\u4e2a\u503c\u90fd\u5360\u7528M\u4e2a\u5b57\u8282\uff0c\u5982\u679c\u67d0\u4e2a\u957f\u5ea6\u5c0f\u4e8eM\uff0cMySQL\u5c31\u4f1a\u5728\u5b83\u7684\u53f3\u8fb9\u7528\u7a7a\u683c\u5b57\u7b26\u8865\u8db3\uff0e\uff08\u5728\u68c0\u7d22\u64cd\u4f5c\u4e2d\u90a3\u4e9b\u586b\u8865\u51fa\u6765\u7684\u7a7a\u683c\u5b57\u7b26\u5c06\u88ab\u53bb\u6389\uff09\u5728varchar(M)\u7c7b\u578b\u7684\u6570\u636e\u5217\u91cc\uff0c\u6bcf\u4e2a\u503c\u53ea\u5360\u7528\u521a\u597d\u591f\u7528\u7684\u5b57\u8282\u518d\u52a0\u4e0a\u4e00\u4e2a\u7528\u6765\u8bb0\u5f55\u5176\u957f\u5ea6\u7684\u5b57\u8282\uff08\u5373\u603b\u957f\u5ea6\u4e3aL+1\u5b57\u8282\uff09\uff0e<\/p>\n<p>&nbsp;<\/p>\n<p>\u5728MySQL\u4e2d\u7528\u6765\u5224\u65ad\u662f\u5426\u9700\u8981\u8fdb\u884c\u5bf9\u636e\u5217\u7c7b\u578b\u8f6c\u6362\u7684\u89c4\u5219<\/p>\n<p>1\u3001\u5728\u4e00\u4e2a\u6570\u636e\u8868\u91cc\uff0c\u5982\u679c\u6bcf\u4e00\u4e2a\u6570\u636e\u5217\u7684\u957f\u5ea6\u90fd\u662f\u56fa\u5b9a\u7684\uff0c\u90a3\u4e48\u6bcf\u4e00\u4e2a\u6570\u636e\u884c\u7684\u957f\u5ea6\u4e5f\u5c06\u662f\u56fa\u5b9a\u7684\uff0e<\/p>\n<p>2\u3001\u53ea\u8981\u6570\u636e\u8868\u91cc\u6709\u4e00\u4e2a\u6570\u636e\u5217\u7684\u957f\u5ea6\u7684\u53ef\u53d8\u7684\uff0c\u90a3\u4e48\u5404\u6570\u636e\u884c\u7684\u957f\u5ea6\u90fd\u662f\u53ef\u53d8\u7684\uff0e<\/p>\n<p>3\u3001\u5982\u679c\u67d0\u4e2a\u6570\u636e\u8868\u91cc\u7684\u6570\u636e\u884c\u7684\u957f\u5ea6\u662f\u53ef\u53d8\u7684\uff0c\u90a3\u4e48\uff0c\u4e3a\u4e86\u8282\u7ea6\u5b58\u50a8\u7a7a\u95f4\uff0cMySQL\u4f1a\u628a\u8fd9\u4e2a\u6570\u636e\u8868\u91cc\u7684\u56fa\u5b9a\u957f\u5ea6\u7c7b\u578b\u7684\u6570\u636e\u5217\u8f6c\u6362\u4e3a\u76f8\u5e94\u7684\u53ef\u53d8\u957f\u5ea6\u7c7b\u578b\uff0e\u4f8b\u5916\uff1a\u957f\u5ea6\u5c0f\u4e8e4\u4e2a\u5b57\u7b26\u7684char\u6570\u636e\u5217\u4e0d\u4f1a\u88ab\u8f6c\u6362\u4e3avarchar\u7c7b\u578b<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>\u88ab\u95ee\u5230\u4e00\u4e2a\u95ee\u9898\uff1aMySQL\u4e2dvarchar\u6700\u5927\u957f\u5ea6\u662f\u591a\u5c11\uff1f\u8fd9\u4e0d\u662f\u4e00\u4e2a\u56fa\u5b9a\u7684\u6570\u5b57\u3002\u672c\u6587\u7b80\u8981\u8bf4\u660e\u4e00\u4e0b\u9650\u5236\u89c4\u5219\u3002<\/p>\n<p>&nbsp;<\/p>\n<p><strong>1\u3001\u9650\u5236\u89c4\u5219<\/strong><\/p>\n<p>\u5b57\u6bb5\u7684\u9650\u5236\u5728\u5b57\u6bb5\u5b9a\u4e49\u7684\u65f6\u5019\u6709\u4ee5\u4e0b\u89c4\u5219\uff1a<\/p>\n<p>&nbsp;<\/p>\n<p>a)\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u5b58\u50a8\u9650\u5236<\/p>\n<p>varchar\u00a0\u5b57\u6bb5\u662f\u5c06\u5b9e\u9645\u5185\u5bb9\u5355\u72ec\u5b58\u50a8\u5728\u805a\u7c07\u7d22\u5f15\u4e4b\u5916\uff0c\u5185\u5bb9\u5f00\u5934\u75281\u52302\u4e2a\u5b57\u8282\u8868\u793a\u5b9e\u9645\u957f\u5ea6\uff08\u957f\u5ea6\u8d85\u8fc7255\u65f6\u9700\u89812\u4e2a\u5b57\u8282\uff09\uff0c\u56e0\u6b64\u6700\u5927\u957f\u5ea6\u4e0d\u80fd\u8d85\u8fc765535\u3002<\/p>\n<p>&nbsp;<\/p>\n<p>b)\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u7f16\u7801\u957f\u5ea6\u9650\u5236<\/p>\n<p>\u5b57\u7b26\u7c7b\u578b\u82e5\u4e3agbk\uff0c\u6bcf\u4e2a\u5b57\u7b26\u6700\u591a\u53602\u4e2a\u5b57\u8282\uff0c\u6700\u5927\u957f\u5ea6\u4e0d\u80fd\u8d85\u8fc732766;<\/p>\n<p>\u5b57\u7b26\u7c7b\u578b\u82e5\u4e3autf8\uff0c\u6bcf\u4e2a\u5b57\u7b26\u6700\u591a\u53603\u4e2a\u5b57\u8282\uff0c\u6700\u5927\u957f\u5ea6\u4e0d\u80fd\u8d85\u8fc721845\u3002<\/p>\n<p>\u82e5\u5b9a\u4e49\u7684\u65f6\u5019\u8d85\u8fc7\u4e0a\u8ff0\u9650\u5236\uff0c\u5219varchar\u5b57\u6bb5\u4f1a\u88ab\u5f3a\u884c\u8f6c\u4e3atext\u7c7b\u578b\uff0c\u5e76\u4ea7\u751fwarning\u3002<\/p>\n<p>&nbsp;<\/p>\n<p>c)\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u884c\u957f\u5ea6\u9650\u5236<\/p>\n<p>\u5bfc\u81f4\u5b9e\u9645\u5e94\u7528\u4e2dvarchar\u957f\u5ea6\u9650\u5236\u7684\u662f\u4e00\u4e2a\u884c\u5b9a\u4e49\u7684\u957f\u5ea6\u3002\u00a0MySQL\u8981\u6c42\u4e00\u4e2a\u884c\u7684\u5b9a\u4e49\u957f\u5ea6\u4e0d\u80fd\u8d85\u8fc765535\u3002\u82e5\u5b9a\u4e49\u7684\u8868\u957f\u5ea6\u8d85\u8fc7\u8fd9\u4e2a\u503c\uff0c\u5219\u63d0\u793a<\/p>\n<p>ERROR 1118 (42000): Row size too large. The maximum row size for the used table type, not counting BLOBs, is 65535. You have to change some columns to TEXT or BLOBs\u3002<\/p>\n<p>&nbsp;<\/p>\n<p><strong>2\u3001\u8ba1\u7b97\u4f8b\u5b50<\/strong><\/p>\n<p>\u4e3e\u4e24\u4e2a\u4f8b\u8bf4\u660e\u4e00\u4e0b\u5b9e\u9645\u957f\u5ea6\u7684\u8ba1\u7b97\u3002<\/p>\n<p>&nbsp;<\/p>\n<p>a)\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u82e5\u4e00\u4e2a\u8868\u53ea\u6709\u4e00\u4e2avarchar\u7c7b\u578b\uff0c\u5982\u5b9a\u4e49\u4e3a<\/p>\n<p>create table t4(c varchar(N)) charset=gbk;<\/p>\n<p>\u5219\u6b64\u5904N\u7684\u6700\u5927\u503c\u4e3a(65535-1-2)\/2=\u00a032766\u3002<\/p>\n<p>\u51cf1\u7684\u539f\u56e0\u662f\u5b9e\u9645\u884c\u5b58\u50a8\u4ece\u7b2c\u4e8c\u4e2a\u5b57\u8282\u5f00\u59cb\u2019;<\/p>\n<p>\u51cf2\u7684\u539f\u56e0\u662fvarchar\u5934\u90e8\u76842\u4e2a\u5b57\u8282\u8868\u793a\u957f\u5ea6;<\/p>\n<p>\u96642\u7684\u539f\u56e0\u662f\u5b57\u7b26\u7f16\u7801\u662fgbk\u3002<\/p>\n<p>&nbsp;<\/p>\n<p>b)\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u82e5\u4e00\u4e2a\u8868\u5b9a\u4e49\u4e3a<\/p>\n<p>create table t4(c int, c2 char(30), c3 varchar(N)) charset=utf8;<\/p>\n<p>\u5219\u6b64\u5904N\u7684\u6700\u5927\u503c\u4e3a\u00a0(65535-1-2-4-30*3)\/3=21812<\/p>\n<p>\u51cf1\u548c\u51cf2\u4e0e\u4e0a\u4f8b\u76f8\u540c;<\/p>\n<p>\u51cf4\u7684\u539f\u56e0\u662fint\u7c7b\u578b\u7684c\u53604\u4e2a\u5b57\u8282;<\/p>\n<p>\u51cf30*3\u7684\u539f\u56e0\u662fchar(30)\u5360\u752890\u4e2a\u5b57\u8282\uff0c\u7f16\u7801\u662futf8\u3002<\/p>\n<p>&nbsp;<\/p>\n<p>\u5982\u679c\u88abvarchar\u8d85\u8fc7\u4e0a\u8ff0\u7684b\u89c4\u5219\uff0c\u88ab\u5f3a\u8f6c\u6210text\u7c7b\u578b\uff0c\u5219\u6bcf\u4e2a\u5b57\u6bb5\u5360\u7528\u5b9a\u4e49\u957f\u5ea6\u4e3a11\u5b57\u8282\uff0c\u5f53\u7136\u8fd9\u5df2\u7ecf\u4e0d\u662f\u201cvarchar\u201d\u4e86\u3002<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p><strong>\u5219\u6b64\u5904N\u7684\u6700\u5927\u503c\u4e3a\u00a0(65535-1-2-4-30*3)\/3=21812<\/strong><\/p>\n<p>&nbsp;<\/p>\n<p><strong>create table t4(c int, c2 char(30), c3 varchar(21812)) ENGINE=InnoDB DEFAULT CHARSET=utf8<\/strong><\/p>\n<p><strong>\u00a0<\/strong><\/p>\n<p><strong>create table t5(c int, c2 varchar(30), c3 varchar(21812)) ENGINE=InnoDB DEFAULT CHARSET=utf8<\/strong><\/p>\n<div><strong>\u00a0<\/strong><\/div>\n<div><strong>varchar(30)\u548cchar(30)\u6700\u591a\u80fd\u5b58\u653e\uff1a<\/strong><\/div>\n<div><strong>\u5de5\u5728\u57fa\u5de5\u5de6\u57fa\u5de5\u5728\u57fa\u987a\u5de5\u4f5c\u5954\u5927\u89c4\u6a21\u96c6\u6210\u7535\u8def\u57ce\u5de5\u4f5c\u4e1c\u5954\u897f\u8d70\u5de6\u593a\u5de5\u57ce\u97af\u9769\u57ce\u8f7d\u6a21\u538b\u5730\u5de5\u9b42\u7275\u68a6\u8426\u683d\u571f\u6728\u5de5\u7a0b\u9b42\u7275\u68a6\u8426\u683d\u690d\u5947\u5de7\u9b42\u7275\u68a6\u8426\u5730\u5385\u57ce\u67d1\u6a21\u538b\u4e1c\u5954\u897f\u8d70\u82e6\u6751\u843d\u6a21\u538b\u9769\u9769\u67d1\u53ef\u8015\u5730\u6751\u6a21\u538b\u57fa\u683d\u9b42\u7275\u68a6\u57fa<\/strong><\/div>\n<div><strong>\u00a0<\/strong><\/div>\n<div><strong>aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa<\/strong><\/div>\n<div><strong>aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa<\/strong><\/div>\n<div><strong>\u00a0<\/strong><\/div>\n<div><strong>111111111111111111111111111111111111111111111111111111<\/strong><\/div>\n<div><strong>111111111111111111111111111111111111<\/strong><\/div>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>CREATE TABLE `t` (<br \/>\n`var` varchar(21844) default NULL<br \/>\n) ENGINE=InnoDB DEFAULT CHARSET=utf8<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>\u53ef\u4ee5\u6b63\u5e38\u7684\u6267\u884c\u3002<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>[SQL] CREATE TABLE `t` (<\/p>\n<p>`var` varchar(21845) default NULL<\/p>\n<p>) ENGINE=InnoDB DEFAULT CHARSET=utf8<\/p>\n<p>&nbsp;<\/p>\n<p>[Err] 1118 &#8211; Row size too large. The maximum row size for the used table type, not counting BLOBs, is 65535. You have to change some columns to TEXT or BLOBs<\/p>\n<div>\u6267\u884c\u6709\u9519\u8bef<\/div>\n<div><\/div>\n<div><\/div>\n<div><\/div>\n<div><\/div>\n<div><\/div>\n<div><\/div>\n<div>\n<h3>[MySQL]\u5982\u4f55\u8ba1\u7b97varchar\u6700\u5927\u957f\u5ea6<\/h3>\n<\/div>\n<div>\u8fd9\u91cc\u6709\u4e00\u9053\u6211YY\u51fa\u6765\u7684\u5173\u4e8eMySQL\u7684\u9898\uff1a<br \/>\n\u8868\u8bbe\u8ba1\u5982\u4e0b<\/p>\n<table border=\"1\" cellspacing=\"1\" cellpadding=\"1\">\n<tbody>\n<tr>\n<td>\u00a0 id<\/td>\n<td>\u00a0mediumint<\/td>\n<\/tr>\n<tr>\n<td>\u00a0name<\/td>\n<td>\u00a0varchar<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u95ee\u9898\u662f\uff1a\u00a0 MySQL5.1 ,\u00a0 \u5728GBK\u5b57\u7b26\u73af\u5883\u4e0b\uff0c\u8fd9\u91cc\u7684varchar\u6700\u957f\u80fd\u8bbe\u591a\u957f\uff1f<\/p>\n<p>\u6b63\u786e\u7b54\u6848\u662f\uff1a 32764<\/p>\n<p>\u90a3\u5982\u679c\u8868\u8bbe\u8ba1\u4e3a\u4e24\u4e2a varchar,\u00a0\u00a0 \u7b2c\u4e00\u4e2a\u957f\u5ea6\u8bbe\u4e3a300\u65f6\uff0c\u7b2c\u4e8c\u4e2avarchar\u5e94\u8be5\u591a\u957f\uff1f\u00a0 &#8211;\u7b54\u6848\u89c1\u672c\u6587\u6700\u540e\u9762<\/p>\n<p>\u8981\u60f3\u641e\u660e\u767d\u662f\u600e\u4e48\u7b97\u51fa\u6765\u7684\uff0c\u8bf7\u4ed4\u7ec6\u4e0b\u9762\u7684\u89e3\u91ca\uff1a<br \/>\n\u5b98\u65b9\u6587\u6863\u4e0a\u5bf9 int \u53ca varchar \u7684\u8bf4\u660e\u5982\u4e0b\uff1a<br \/>\n<img alt=\"\" \/><\/p>\n<p><iframe id=\"iframe_0.6270769424651017\" width=\"300\" height=\"150\" frameborder=\"0\" scrolling=\"no\" data-mce-fragment=\"1\"><\/iframe><\/p>\n<p>Values in VARCHAR columns are variable-length strings. The length can be specified as a value from 0 to 255 before MySQL 5.0.3, and 0 to 65,535 in 5.0.3 and later versions.<\/p>\n<p>\u770b\u5230\u8fd9\u91cc\uff0c\u4f60\u4ee5\u4e3a\u4e0a\u9762\u7684varchar\u957f\u5ea6\u662f\uff1a 65535 \/2\uff1d32767\uff1f<br \/>\n\u4e0d\u5bf9\uff0c\u56e0\u4e3a\u5b98\u65b9\u6587\u6863\u540e\u9762\u53c8\u8bf4\uff1a<br \/>\nIn contrast to CHAR, VARCHAR values are stored as a one-byte or two-byte length prefix plus data. The length prefix indicates the number of bytes in the value.<br \/>\n\u5f88\u660e\u767d\u4e86\uff0cvarchar\u4f1a\u4fdd\u7559\u4e00\u81f3\u4e24\u4e2a\u5b57\u8282\u6765\u5b58\u653e\u957f\u5ea6\u4fe1\u606f\uff0c\u4f46\u5230\u5e95\u662f1Byte\u8fd8\u662f2Byte\uff1f<br \/>\n\u5f80\u540e\u770b\uff1a<br \/>\nA column uses one length byte if values require no more than 255 bytes, two length bytes if values may require<br \/>\nmore than 255 bytes.<br \/>\n\u4f60\u518d\u6765\u7b97\u4e00\u7b97varchar\u957f\u5ea6 \u6700\u5927\u4e3a\uff1a (65535-2) \/2 = 32766 ?<br \/>\n\u8fd8\u662f\u4e0d\u5bf9\uff01<br \/>\n\u5176\u5b9e\u6bcf\u4e00\u884c\u7684\u603b\u957f\u5ea6\u662f\u6709\u9650\u5236\u7684\uff0c\u5373\u6700\u5927\u4e3a65535.<br \/>\nEvery table has a maximum row size of 65,535 bytes.<br \/>\nThis maximum applies to all storage engines, but a given engine might have additional constraints that result in a lower effective maximum row size.<br \/>\n\u6240\u4ee5\u7b97varchar\u5f97\u628aid\u7684\u6263\u9664\uff1a<br \/>\n(65535-3-2) \/2 = 32765 ?<\/p>\n<p>\u6d4b\u8bd5\u4e00\u4e0b\uff1a<br \/>\nroot@saker 05:27:28&gt;create table t4(id mediumint, name varchar(32765));<br \/>\nERROR 1118 (42000): Row size too large. The maximum row size for the used table type, not counting BLOBs, is 65535. You have to change some columns to TEXT or BLOBs<\/p>\n<p>\u752832764\u6d4b\u8bd5\u4e00\u4e0b\uff1a<br \/>\nroot@saker 05:27:31&gt;create table t4(id mediumint, name varchar(32764));<br \/>\nQuery OK, 0 rows affected (0.16 sec)<\/p>\n<p>root@saker 05:27:35&gt;desc t4;<br \/>\n+&#8212;&#8212;-+&#8212;&#8212;&#8212;&#8212;&#8212;-+&#8212;&#8212;+&#8212;&#8211;+&#8212;&#8212;&#8212;+&#8212;&#8212;-+<br \/>\n| Field | Type\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 | Null | Key | Default | Extra |<br \/>\n+&#8212;&#8212;-+&#8212;&#8212;&#8212;&#8212;&#8212;-+&#8212;&#8212;+&#8212;&#8211;+&#8212;&#8212;&#8212;+&#8212;&#8212;-+<br \/>\n| id\u00a0\u00a0\u00a0 | mediumint(9)\u00a0\u00a0 | YES\u00a0 |\u00a0\u00a0\u00a0\u00a0 | NULL\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |<br \/>\n| name\u00a0 | varchar(32764) | YES\u00a0 |\u00a0\u00a0\u00a0\u00a0 | NULL\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |<br \/>\n+&#8212;&#8212;-+&#8212;&#8212;&#8212;&#8212;&#8212;-+&#8212;&#8212;+&#8212;&#8211;+&#8212;&#8212;&#8212;+&#8212;&#8212;-+<\/p>\n<p>\u8fd9\u8bf4\u660e\u8fd8\u4fdd\u7559\u4e861\u81f32\u4e2a\u5b57\u8282\u6765\u7559\u5176\u5b83\u63a7\u5236\u4fe1\u606f\u3002\uff08\u5728\u6587\u6863\u91cc\u9762\u6211\u6ca1\u6709\u627e\u5230\u8bf4\u660e\uff0c\u6240\u4ee5\u4e5f\u4e0d\u77e5\u9053\u5230\u5e95\u662f1\u4e2a\u8fd8\u662f2\u4e2abyte\uff09<br \/>\n\u4f46\u6211\u60f3\u5230\u4e86\u4e00\u4e2a\u65b9\u6cd5\u6765\u53cd\u63a8\u51fa\u6765\uff0c<br \/>\n\u6211\u628aid\u7684\u7c7b\u578b\u4ecemedium\u6539\u6210 int \uff0c\u8fd9\u65f6id\u7684\u957f\u5ea6\u5c31\u4ece3\u53d8\u4e3a4\u4e86\uff0c\u5982\u679c\u63a7\u5236\u5b57\u8282\u7528\u4e862Bytes\uff0c\u90a3varchar\u7684\u957f\u5ea6\u8fd8\u8bbe\u4e3a32764\u7684\u8bdd\uff0c\u663e\u7136\u662f\u8981\u62a5\u9519\u7684\u3002\u3002\u3002<br \/>\nroot@saker 05:29:14&gt;create table t3(id int, name varchar(32764));<br \/>\nQuery OK, 0 rows affected (0.18 sec)<br \/>\nroot@saker 07:01:10&gt;desc t3;<br \/>\n+&#8212;&#8212;-+&#8212;&#8212;&#8212;&#8212;&#8212;-+&#8212;&#8212;+&#8212;&#8211;+&#8212;&#8212;&#8212;+&#8212;&#8212;-+<br \/>\n| Field | Type\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 | Null | Key | Default | Extra |<br \/>\n+&#8212;&#8212;-+&#8212;&#8212;&#8212;&#8212;&#8212;-+&#8212;&#8212;+&#8212;&#8211;+&#8212;&#8212;&#8212;+&#8212;&#8212;-+<br \/>\n| id\u00a0\u00a0\u00a0 | int(11)\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 | YES\u00a0 |\u00a0\u00a0\u00a0\u00a0 | NULL\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |<br \/>\n| name\u00a0 | varchar(32764) | YES\u00a0 |\u00a0\u00a0\u00a0\u00a0 | NULL\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |<br \/>\n+&#8212;&#8212;-+&#8212;&#8212;&#8212;&#8212;&#8212;-+&#8212;&#8212;+&#8212;&#8211;+&#8212;&#8212;&#8212;+&#8212;&#8212;-+<br \/>\n\u8fd9\u6837\u5e94\u8be5\u80fd\u8bf4\u660e\uff0c\u63a7\u5236\u4f4d\u53ea\u67091\u4e2a\u5b57\u8282\u3002<\/p>\n<p>\u4e0b\u9762\u7528\u8fd9\u4e2a\u7ed3\u8bba\u6765\u8ba1\u7b97\u7b2c\u4e8c\u4e2a\u95ee\u9898\uff1a<br \/>\n\u90a3\u5982\u679c\u8868\u8bbe\u8ba1\u4e3a\u4e24\u4e2a varchar,\u00a0\u00a0 \u7b2c\u4e00\u4e2a\u957f\u5ea6\u8bbe\u4e3a300\u65f6\uff0c\u7b2c\u4e8c\u4e2avarchar\u5e94\u8be5\u591a\u957f\uff1f<br \/>\n(65535-1-2-2-300*2) \/2 =\u00a0 32465<br \/>\n\u6d4b\u8bd5\u4e00\u4e0b\uff1a<br \/>\nroot@saker 07:09:23&gt;create table t1(id varchar(300), name varchar(32465));<br \/>\nQuery OK, 0 rows affected (0.15 sec)<\/p>\n<p>root@saker 07:09:26&gt;desc t1;<br \/>\n+&#8212;&#8212;-+&#8212;&#8212;&#8212;&#8212;&#8212;-+&#8212;&#8212;+&#8212;&#8211;+&#8212;&#8212;&#8212;+&#8212;&#8212;-+<br \/>\n| Field | Type\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 | Null | Key | Default | Extra |<br \/>\n+&#8212;&#8212;-+&#8212;&#8212;&#8212;&#8212;&#8212;-+&#8212;&#8212;+&#8212;&#8211;+&#8212;&#8212;&#8212;+&#8212;&#8212;-+<br \/>\n| id\u00a0\u00a0\u00a0 | varchar(300)\u00a0\u00a0 | YES\u00a0 |\u00a0\u00a0\u00a0\u00a0 | NULL\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |<br \/>\n| name\u00a0 | varchar(32465) | YES\u00a0 |\u00a0\u00a0\u00a0\u00a0 | NULL\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |<br \/>\n+&#8212;&#8212;-+&#8212;&#8212;&#8212;&#8212;&#8212;-+&#8212;&#8212;+&#8212;&#8211;+&#8212;&#8212;&#8212;+&#8212;&#8212;-+<br \/>\n2 rows in set (0.02 sec)<\/p>\n<p>\u591a\u4e00\u4f4d\u90fd\u4e0d\u884c\uff1a<br \/>\nroot@saker 07:08:12&gt;create table t1(id varchar(300), name varchar(32466));<br \/>\nERROR 1118 (42000): Row size too large. The maximum row size for the used table type, not counting BLOBs, is 65535. You have to change some columns to TEXT or BLOBs<\/p>\n<p>\u6700\u540e \u628a\u4ee5\u4e0a\u6240\u6709\u77e5\u8bc6\u7efc\u5408\u8d77\u6765\uff1a<br \/>\n\u6709\u4e00\u4e2a\u8868\uff1a<br \/>\nid int,\u00a0\u00a0 name1 char(20),\u00a0 name2 varchar(100), name3 varchar(?)<\/p>\n<p>\u7b97\u4e00\u4e0b\uff1a<br \/>\n(65535-1-1-2-4-20*2-100*2) \/2 \uff1d 32643<\/p>\n<p>root@saker 07:16:09&gt;create table tt(id int, name1 char(20), name2 varchar(100), name3 varchar(32643));<br \/>\nQuery OK, 0 rows affected (0.18 sec)<\/p>\n<p>root@saker 07:16:12&gt;desc tt;<br \/>\n+&#8212;&#8212;-+&#8212;&#8212;&#8212;&#8212;&#8212;-+&#8212;&#8212;+&#8212;&#8211;+&#8212;&#8212;&#8212;+&#8212;&#8212;-+<br \/>\n| Field | Type\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 | Null | Key | Default | Extra |<br \/>\n+&#8212;&#8212;-+&#8212;&#8212;&#8212;&#8212;&#8212;-+&#8212;&#8212;+&#8212;&#8211;+&#8212;&#8212;&#8212;+&#8212;&#8212;-+<br \/>\n| id\u00a0\u00a0\u00a0 | int(11)\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 | YES\u00a0 |\u00a0\u00a0\u00a0\u00a0 | NULL\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |<br \/>\n| name1 | char(20)\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 | YES\u00a0 |\u00a0\u00a0\u00a0\u00a0 | NULL\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |<br \/>\n| name2 | varchar(100)\u00a0\u00a0 | YES\u00a0 |\u00a0\u00a0\u00a0\u00a0 | NULL\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |<br \/>\n| name3 | varchar(32643) | YES\u00a0 |\u00a0\u00a0\u00a0\u00a0 | NULL\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |<br \/>\n+&#8212;&#8212;-+&#8212;&#8212;&#8212;&#8212;&#8212;-+&#8212;&#8212;+&#8212;&#8211;+&#8212;&#8212;&#8212;+&#8212;&#8212;-+<br \/>\n4 rows in set (0.00 sec)<\/p>\n<p>root@saker 07:15:08&gt;create table tt(id int, name1 char(20), name2 varchar(100), name3 varchar(32644));<br \/>\nERROR 1118 (42000): Row size too large. The maximum row size for the used table type, not counting BLOBs, is 65535. You have to change some columns to TEXT or BLOBs<\/p>\n<p>\u6240\u4ee5\u8bbe\u8ba1\u8868\u7684\u65f6\u5019\uff0c\u8fd9\u4e2a\u8981\u6ce8\u610f\u4e86\uff0c\u6bcf\u4e00\u884c\u662f\u6709\u957f\u5ea6\u9650\u5236\u7684\u3002<\/p><\/div>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>\u4e00. varchar\u5b58\u50a8\u89c4\u5219\uff1a 4.0\u7248\u672c\u4ee5\u4e0b\uff0cvarchar(20)\uff0c\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 5.0\u7248\u672c\u4ee5\u4e0a\uff0cvarchar(20)\uff0c\u6307\u7684\u662f20\u5b57\u7b26\uff0c\u65e0\u8bba\u5b58\u653e\u7684\u662f\u6570\u5b57\u3001\u5b57\u6bcd\u8fd8\u662fUTF8\u6c49\u5b57\uff08\u6bcf\u4e2a\u6c49\u5b573\u5b57\u8282\uff09\uff0c\u90fd\u53ef\u4ee5\u5b58\u653e20\u4e2a\uff0c\u6700\u5927\u5927\u5c0f\u662f65532\u5b57\u8282 Mysql4\u4e2d\u6700\u5927\u4e5f\u4e0d\u8fc7\u662f20\u4e2a\u5b57\u8282,\u4f46\u662fMysql5\u6839\u636e\u7f16\u7801\u4e0d\u540c,\u5b58\u50a8\u5927\u5c0f\u4e5f\u4e0d\u540c\u3002 &nbsp; \u4e8c. varchar\u548cchar \u7684\u533a\u522b\uff1a char\u662f\u4e00\u79cd\u56fa\u5b9a\u957f\u5ea6\u7684\u7c7b\u578b\uff0cvarchar\u5219\u662f\u4e00\u79cd\u53ef\u53d8\u957f\u5ea6\u7684\u7c7b\u578b\uff0c\u5b83\u4eec\u7684\u533a\u522b\u662f\uff1a char(M)\u7c7b\u578b\u7684\u6570\u636e\u5217\u91cc\uff0c\u6bcf\u4e2a\u503c\u90fd\u5360\u7528M\u4e2a\u5b57\u8282\uff0c\u5982\u679c\u67d0\u4e2a\u957f\u5ea6\u5c0f\u4e8eM\uff0cMySQL\u5c31\u4f1a\u5728\u5b83\u7684\u53f3\u8fb9\u7528\u7a7a\u683c\u5b57\u7b26\u8865\u8db3\uff0e\uff08\u5728\u68c0\u7d22\u64cd\u4f5c\u4e2d\u90a3\u4e9b\u586b\u8865\u51fa\u6765\u7684\u7a7a\u683c\u5b57\u7b26\u5c06\u88ab\u53bb\u6389\uff09\u5728varchar(M)\u7c7b\u578b\u7684\u6570\u636e\u5217\u91cc\uff0c\u6bcf\u4e2a\u503c\u53ea\u5360\u7528\u521a\u597d\u591f\u7528\u7684\u5b57\u8282\u518d\u52a0\u4e0a\u4e00\u4e2a\u7528\u6765\u8bb0\u5f55\u5176\u957f\u5ea6\u7684\u5b57\u8282\uff08\u5373\u603b\u957f\u5ea6\u4e3aL+1\u5b57\u8282\uff09\uff0e &nbsp; \u5728MySQL\u4e2d\u7528\u6765\u5224\u65ad\u662f\u5426\u9700\u8981\u8fdb\u884c\u5bf9\u636e\u5217\u7c7b\u578b\u8f6c\u6362\u7684\u89c4\u5219 1\u3001\u5728\u4e00\u4e2a\u6570\u636e\u8868\u91cc\uff0c\u5982\u679c\u6bcf\u4e00\u4e2a\u6570\u636e\u5217\u7684\u957f\u5ea6\u90fd\u662f\u56fa\u5b9a\u7684\uff0c\u90a3\u4e48\u6bcf\u4e00\u4e2a\u6570\u636e\u884c\u7684\u957f\u5ea6\u4e5f\u5c06\u662f\u56fa\u5b9a\u7684\uff0e 2\u3001\u53ea\u8981\u6570\u636e\u8868\u91cc\u6709\u4e00\u4e2a\u6570\u636e\u5217\u7684\u957f\u5ea6\u7684\u53ef\u53d8\u7684\uff0c\u90a3\u4e48\u5404\u6570\u636e\u884c\u7684\u957f\u5ea6\u90fd\u662f\u53ef\u53d8\u7684\uff0e 3\u3001\u5982\u679c\u67d0\u4e2a\u6570\u636e\u8868\u91cc\u7684\u6570\u636e\u884c\u7684\u957f\u5ea6\u662f\u53ef\u53d8\u7684\uff0c\u90a3\u4e48\uff0c\u4e3a\u4e86\u8282\u7ea6\u5b58\u50a8\u7a7a\u95f4\uff0cMySQL\u4f1a\u628a\u8fd9\u4e2a\u6570\u636e\u8868\u91cc\u7684\u56fa\u5b9a\u957f\u5ea6\u7c7b\u578b\u7684\u6570\u636e\u5217\u8f6c\u6362\u4e3a\u76f8\u5e94\u7684\u53ef\u53d8\u957f\u5ea6\u7c7b\u578b\uff0e\u4f8b\u5916\uff1a\u957f\u5ea6\u5c0f\u4e8e4\u4e2a\u5b57\u7b26\u7684char\u6570\u636e\u5217\u4e0d\u4f1a\u88ab\u8f6c\u6362\u4e3avarchar\u7c7b\u578b &nbsp; 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