{"id":77848,"date":"2024-10-16T11:14:40","date_gmt":"2024-10-16T03:14:40","guid":{"rendered":"https:\/\/server.hk\/cnblog\/77848\/"},"modified":"2024-10-16T11:14:40","modified_gmt":"2024-10-16T03:14:40","slug":"mysql%e6%8c%87%e4%bb%a4-char_length%ef%bc%88%e5%ad%97%e7%ac%a6%e9%95%b7%e5%ba%a6%ef%bc%89","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/77848\/","title":{"rendered":"MySQL\u6307\u4ee4: CHAR_LENGTH()\uff08\u5b57\u7b26\u9577\u5ea6\uff09"},"content":{"rendered":"<h1 id=\"mysql%e6%8c%87%e4%bb%a4-char_length%ef%bc%88%e5%ad%97%e7%ac%a6%e9%95%b7%e5%ba%a6%ef%bc%89-DcZkWqDqCg\">MySQL\u6307\u4ee4: CHAR_LENGTH()\uff08\u5b57\u7b26\u9577\u5ea6\uff09<\/h1>\n<p>\u5728\u6578\u64da\u5eab\u7ba1\u7406\u4e2d\uff0cMySQL\u662f\u4e00\u500b\u5ee3\u6cdb\u4f7f\u7528\u7684\u95dc\u806f\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\u3002\u5b83\u63d0\u4f9b\u4e86\u591a\u7a2e\u529f\u80fd\u4f86\u8655\u7406\u548c\u5206\u6790\u6578\u64da\uff0c\u5176\u4e2d\u4e4b\u4e00\u5c31\u662f\u8a08\u7b97\u5b57\u7b26\u4e32\u7684\u5b57\u7b26\u9577\u5ea6\u3002\u9019\u88e1\uff0c\u6211\u5011\u5c07\u6df1\u5165\u63a2\u8a0eMySQL\u4e2d\u7684CHAR_LENGTH()\u51fd\u6578\uff0c\u4e26\u4e86\u89e3\u5b83\u7684\u7528\u6cd5\u53ca\u5176\u5728\u5be6\u969b\u61c9\u7528\u4e2d\u7684\u91cd\u8981\u6027\u3002<\/p>\n<h2 id=\"char_length%e5%87%bd%e6%95%b8%e6%a6%82%e8%bf%b0-DcZkWqDqCg\">CHAR_LENGTH()\u51fd\u6578\u6982\u8ff0<\/h2>\n<p>CHAR_LENGTH()\u51fd\u6578\u7528\u65bc\u8fd4\u56de\u5b57\u7b26\u4e32\u4e2d\u7684\u5b57\u7b26\u6578\u3002\u9019\u500b\u51fd\u6578\u5c0d\u65bc\u9700\u8981\u78ba\u5b9a\u5b57\u7b26\u4e32\u9577\u5ea6\u7684\u60c5\u6cc1\u7279\u5225\u6709\u7528\uff0c\u4f8b\u5982\u5728\u6578\u64da\u9a57\u8b49\u3001\u5831\u544a\u751f\u6210\u6216\u6578\u64da\u5206\u6790\u4e2d\u3002<\/p>\n<h3 id=\"%e8%aa%9e%e6%b3%95-DcZkWqDqCg\">\u8a9e\u6cd5<\/h3>\n<pre><code>CHAR_LENGTH(string)<\/code><\/pre>\n<p>\u5728\u9019\u88e1\uff0c<code>string<\/code>\u662f\u8981\u8a08\u7b97\u5b57\u7b26\u9577\u5ea6\u7684\u5b57\u7b26\u4e32\u3002CHAR_LENGTH()\u51fd\u6578\u5c07\u8fd4\u56de\u4e00\u500b\u6574\u6578\uff0c\u8868\u793a\u8a72\u5b57\u7b26\u4e32\u4e2d\u7684\u5b57\u7b26\u6578\u3002<\/p>\n<h2 id=\"%e4%bd%bf%e7%94%a8%e7%af%84%e4%be%8b-DcZkWqDqCg\">\u4f7f\u7528\u7bc4\u4f8b<\/h2>\n<p>\u4ee5\u4e0b\u662f\u4e00\u4e9b\u4f7f\u7528CHAR_LENGTH()\u51fd\u6578\u7684\u7bc4\u4f8b\uff1a<\/p>\n<h3 id=\"%e7%af%84%e4%be%8b1-%e5%9f%ba%e6%9c%ac%e7%94%a8%e6%b3%95-DcZkWqDqCg\">\u7bc4\u4f8b1: \u57fa\u672c\u7528\u6cd5<\/h3>\n<pre><code>SELECT CHAR_LENGTH('Hello, World!') AS length;<\/code><\/pre>\n<p>\u9019\u500b\u67e5\u8a62\u5c07\u8fd4\u56de\u5b57\u7b26\u4e32\u201cHello, World!\u201d\u7684\u5b57\u7b26\u9577\u5ea6\uff0c\u7d50\u679c\u70ba13\u3002<\/p>\n<h3 id=\"%e7%af%84%e4%be%8b2-%e5%9c%a8%e8%a1%a8%e4%b8%ad%e4%bd%bf%e7%94%a8-DcZkWqDqCg\">\u7bc4\u4f8b2: \u5728\u8868\u4e2d\u4f7f\u7528<\/h3>\n<p>\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u540d\u70ba<code>users<\/code>\u7684\u8868\uff0c\u8a72\u8868\u5305\u542b\u7528\u6236\u7684\u59d3\u540d\u3002\u4ee5\u4e0b\u67e5\u8a62\u5c07\u8fd4\u56de\u6bcf\u500b\u7528\u6236\u59d3\u540d\u7684\u5b57\u7b26\u9577\u5ea6\uff1a<\/p>\n<pre><code>SELECT name, CHAR_LENGTH(name) AS name_length FROM users;<\/code><\/pre>\n<p>\u9019\u5c07\u986f\u793a\u6bcf\u500b\u7528\u6236\u7684\u59d3\u540d\u53ca\u5176\u5c0d\u61c9\u7684\u5b57\u7b26\u9577\u5ea6\uff0c\u65b9\u4fbf\u9032\u884c\u6578\u64da\u5206\u6790\u3002<\/p>\n<h3 id=\"%e7%af%84%e4%be%8b3-%e7%b5%90%e5%90%88where%e5%ad%90%e5%8f%a5-DcZkWqDqCg\">\u7bc4\u4f8b3: \u7d50\u5408WHERE\u5b50\u53e5<\/h3>\n<p>\u6211\u5011\u4e5f\u53ef\u4ee5\u4f7f\u7528CHAR_LENGTH()\u51fd\u6578\u4f86\u904e\u6ffe\u6578\u64da\u3002\u4f8b\u5982\uff0c\u4ee5\u4e0b\u67e5\u8a62\u5c07\u8fd4\u56de\u6240\u6709\u59d3\u540d\u9577\u5ea6\u5927\u65bc5\u7684\u7528\u6236\uff1a<\/p>\n<pre><code>SELECT * FROM users WHERE CHAR_LENGTH(name) &gt; 5;<\/code><\/pre>\n<p>\u9019\u6a23\u53ef\u4ee5\u5feb\u901f\u627e\u5230\u7b26\u5408\u7279\u5b9a\u689d\u4ef6\u7684\u6578\u64da\uff0c\u5c0d\u65bc\u6578\u64da\u6e05\u7406\u548c\u5206\u6790\u975e\u5e38\u6709\u5e6b\u52a9\u3002<\/p>\n<h2 id=\"char_length%e8%88%87length%e7%9a%84%e5%8d%80%e5%88%a5-DcZkWqDqCg\">CHAR_LENGTH()\u8207LENGTH()\u7684\u5340\u5225<\/h2>\n<p>\u5728MySQL\u4e2d\uff0c\u9084\u6709\u4e00\u500b\u985e\u4f3c\u7684\u51fd\u6578\u53eb\u505aLENGTH()\u3002\u9019\u5169\u8005\u4e4b\u9593\u7684\u4e3b\u8981\u5340\u5225\u5728\u65bc\uff1a<\/p>\n<ul>\n<li><strong>CHAR_LENGTH()<\/strong>: \u8fd4\u56de\u5b57\u7b26\u4e32\u4e2d\u7684\u5b57\u7b26\u6578\uff0c\u5c0d\u65bc\u591a\u5b57\u7bc0\u5b57\u7b26\uff08\u5982\u4e2d\u6587\uff09\u4e5f\u80fd\u6b63\u78ba\u8a08\u7b97\u3002<\/li>\n<li><strong>LENGTH()<\/strong>: \u8fd4\u56de\u5b57\u7b26\u4e32\u7684\u5b57\u7bc0\u6578\uff0c\u5c0d\u65bc\u591a\u5b57\u7bc0\u5b57\u7b26\uff0c\u8fd4\u56de\u7684\u6578\u5b57\u53ef\u80fd\u6703\u5c0f\u65bcCHAR_LENGTH()\u7684\u7d50\u679c\u3002<\/li>\n<\/ul>\n<p>\u56e0\u6b64\uff0c\u5728\u8655\u7406\u591a\u8a9e\u8a00\u5b57\u7b26\u4e32\u6642\uff0c\u4f7f\u7528CHAR_LENGTH()\u6703\u66f4\u70ba\u6e96\u78ba\u3002<\/p>\n<h2 id=\"%e5%af%a6%e9%9a%9b%e6%87%89%e7%94%a8%e5%a0%b4%e6%99%af-DcZkWqDqCg\">\u5be6\u969b\u61c9\u7528\u5834\u666f<\/h2>\n<p>CHAR_LENGTH()\u51fd\u6578\u5728\u591a\u7a2e\u5834\u666f\u4e2d\u90fd\u975e\u5e38\u6709\u7528\uff0c\u4f8b\u5982\uff1a<\/p>\n<ul>\n<li>\u6578\u64da\u9a57\u8b49\uff1a\u78ba\u4fdd\u7528\u6236\u8f38\u5165\u7684\u6578\u64da\u7b26\u5408\u7279\u5b9a\u9577\u5ea6\u8981\u6c42\u3002<\/li>\n<li>\u5831\u544a\u751f\u6210\uff1a\u5728\u751f\u6210\u5831\u544a\u6642\uff0c\u8a08\u7b97\u5b57\u6bb5\u7684\u9577\u5ea6\u4ee5\u4fbf\u65bc\u683c\u5f0f\u5316\u3002<\/li>\n<li>\u6578\u64da\u6e05\u7406\uff1a\u8b58\u5225\u548c\u8655\u7406\u7570\u5e38\u9577\u5ea6\u7684\u6578\u64da\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b8%bd%e7%b5%90-DcZkWqDqCg\">\u7e3d\u7d50<\/h2>\n<p>MySQL\u7684CHAR_LENGTH()\u51fd\u6578\u662f\u4e00\u500b\u5f37\u5927\u7684\u5de5\u5177\uff0c\u80fd\u5920\u5e6b\u52a9\u958b\u767c\u8005\u548c\u6578\u64da\u5206\u6790\u5e2b\u6709\u6548\u5730\u8655\u7406\u548c\u5206\u6790\u5b57\u7b26\u4e32\u6578\u64da\u3002\u7121\u8ad6\u662f\u5728\u6578\u64da\u9a57\u8b49\u3001\u5831\u544a\u751f\u6210\u9084\u662f\u6578\u64da\u6e05\u7406\u4e2d\uff0cCHAR_LENGTH()\u90fd\u80fd\u63d0\u4f9b\u91cd\u8981\u7684\u652f\u6301\u3002\u5c0d\u65bc\u9700\u8981\u9ad8\u6548\u7ba1\u7406\u6578\u64da\u7684\u4f01\u696d\u4f86\u8aaa\uff0c\u9078\u64c7\u5408\u9069\u7684\u6578\u64da\u5eab\u89e3\u6c7a\u65b9\u6848\u81f3\u95dc\u91cd\u8981\u3002\u5982\u679c\u60a8\u6b63\u5728\u5c0b\u627e\u53ef\u9760\u7684 <a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a> \u670d\u52d9\uff0cServer.HK\u63d0\u4f9b\u591a\u7a2e\u9078\u64c7\u4ee5\u6eff\u8db3\u60a8\u7684\u9700\u6c42\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4e86\u89e3MySQL\u6307\u4ee4CHAR_LENGTH()\uff0c\u7528\u65bc\u8a08\u7b97\u5b57\u7b26\u4e32\u7684\u5b57\u7b26\u9577\u5ea6\uff0c\u5e6b\u52a9\u512a\u5316\u6578\u64da\u5eab\u67e5\u8a62\u548c\u6578\u64da\u8655\u7406\u3002<\/p>\n","protected":false},"author":0,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-77848","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/77848","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/types\/post"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=77848"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/77848\/revisions"}],"predecessor-version":[{"id":77849,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/77848\/revisions\/77849"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=77848"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=77848"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=77848"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}