{"id":78912,"date":"2024-10-16T12:28:17","date_gmt":"2024-10-16T04:28:17","guid":{"rendered":"https:\/\/server.hk\/cnblog\/78912\/"},"modified":"2024-10-16T12:28:17","modified_gmt":"2024-10-16T04:28:17","slug":"mysql%e6%8c%87%e4%bb%a4-length%ef%bc%88%e9%95%b7%e5%ba%a6%ef%bc%89","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/78912\/","title":{"rendered":"MySQL\u6307\u4ee4: LENGTH()\uff08\u9577\u5ea6\uff09"},"content":{"rendered":"<h1 id=\"mysql%e6%8c%87%e4%bb%a4-length%ef%bc%88%e9%95%b7%e5%ba%a6%ef%bc%89-DtvNPgdmKC\">MySQL\u6307\u4ee4: LENGTH()\uff08\u9577\u5ea6\uff09<\/h1>\n<p>\u5728\u8cc7\u6599\u5eab\u7ba1\u7406\u7cfb\u7d71\u4e2d\uff0cMySQL\u662f\u4e00\u500b\u5ee3\u6cdb\u4f7f\u7528\u7684\u958b\u6e90\u95dc\u806f\u8cc7\u6599\u5eab\u7ba1\u7406\u7cfb\u7d71\u3002\u5b83\u63d0\u4f9b\u4e86\u591a\u7a2e\u529f\u80fd\u4f86\u8655\u7406\u548c\u7ba1\u7406\u8cc7\u6599\uff0c\u5176\u4e2d\u4e00\u500b\u5e38\u7528\u7684\u51fd\u6578\u662fLENGTH()\u3002\u9019\u500b\u51fd\u6578\u7684\u4e3b\u8981\u4f5c\u7528\u662f\u8a08\u7b97\u5b57\u4e32\u7684\u9577\u5ea6\uff0c\u5c0d\u65bc\u8cc7\u6599\u7684\u8655\u7406\u548c\u5206\u6790\u975e\u5e38\u91cd\u8981\u3002<\/p>\n<h2 id=\"length%e5%87%bd%e6%95%b8%e7%9a%84%e5%9f%ba%e6%9c%ac%e7%94%a8%e6%b3%95-DtvNPgdmKC\">LENGTH()\u51fd\u6578\u7684\u57fa\u672c\u7528\u6cd5<\/h2>\n<p>LENGTH()\u51fd\u6578\u7684\u8a9e\u6cd5\u975e\u5e38\u7c21\u55ae\uff0c\u683c\u5f0f\u5982\u4e0b\uff1a<\/p>\n<pre><code>LENGTH(string)<\/code><\/pre>\n<p>\u5176\u4e2d\uff0c<code>string<\/code>\u662f\u4f60\u60f3\u8981\u8a08\u7b97\u9577\u5ea6\u7684\u5b57\u4e32\u3002\u9019\u500b\u51fd\u6578\u6703\u8fd4\u56de\u5b57\u4e32\u4e2d\u5b57\u7b26\u7684\u6578\u91cf\uff0c\u4e26\u4e14\u8a08\u7b97\u7684\u662f\u5b57\u7bc0\u6578\uff0c\u800c\u4e0d\u662f\u5b57\u7b26\u6578\u3002\u9019\u610f\u5473\u8457\u5c0d\u65bc\u67d0\u4e9b\u591a\u5b57\u7bc0\u5b57\u7b26\uff08\u5982\u4e2d\u6587\uff09\uff0c\u8fd4\u56de\u7684\u9577\u5ea6\u53ef\u80fd\u6703\u5927\u65bc\u5be6\u969b\u7684\u5b57\u7b26\u6578\u3002<\/p>\n<h2 id=\"%e7%af%84%e4%be%8b-DtvNPgdmKC\">\u7bc4\u4f8b<\/h2>\n<p>\u4ee5\u4e0b\u662f\u4e00\u4e9b\u4f7f\u7528LENGTH()\u51fd\u6578\u7684\u7bc4\u4f8b\uff1a<\/p>\n<pre><code>SELECT LENGTH('Hello World');  -- \u8fd4\u56de 11\nSELECT LENGTH('\u4f60\u597d\uff0c\u4e16\u754c');      -- \u8fd4\u56de 15\nSELECT LENGTH('MySQL');          -- \u8fd4\u56de 5\n<\/code><\/pre>\n<p>\u5728\u7b2c\u4e00\u500b\u7bc4\u4f8b\u4e2d\uff0c\u5b57\u4e32\u201cHello World\u201d\u5305\u542b11\u500b\u5b57\u5143\uff08\u5305\u62ec\u7a7a\u683c\uff09\uff0c\u56e0\u6b64\u8fd4\u56de\u7684\u9577\u5ea6\u662f11\u3002\u5728\u7b2c\u4e8c\u500b\u7bc4\u4f8b\u4e2d\uff0c\u5b57\u4e32\u201c\u4f60\u597d\uff0c\u4e16\u754c\u201d\u7531\u65bc\u5305\u542b\u4e2d\u6587\u5b57\u7b26\uff0c\u8fd4\u56de\u7684\u9577\u5ea6\u662f15\uff0c\u56e0\u70ba\u6bcf\u500b\u4e2d\u6587\u5b57\u7b26\u901a\u5e38\u4f54\u75283\u500b\u5b57\u7bc0\u3002\u7b2c\u4e09\u500b\u7bc4\u4f8b\u5247\u986f\u793a\u4e86\u82f1\u6587\u5b57\u6bcd\u7684\u8a08\u7b97\u65b9\u5f0f\u3002<\/p>\n<h2 id=\"length%e8%88%87char_length%e7%9a%84%e5%8d%80%e5%88%a5-DtvNPgdmKC\">LENGTH()\u8207CHAR_LENGTH()\u7684\u5340\u5225<\/h2>\n<p>\u5728MySQL\u4e2d\uff0c\u9664\u4e86LENGTH()\u51fd\u6578\u5916\uff0c\u9084\u6709\u4e00\u500b\u985e\u4f3c\u7684\u51fd\u6578\u53eb\u505aCHAR_LENGTH()\u3002\u9019\u5169\u8005\u7684\u4e3b\u8981\u5340\u5225\u5728\u65bc\u8a08\u7b97\u7684\u65b9\u5f0f\uff1a<\/p>\n<ul>\n<li><strong>LENGTH()<\/strong>\uff1a\u8fd4\u56de\u5b57\u4e32\u7684\u5b57\u7bc0\u6578\u3002<\/li>\n<li><strong>CHAR_LENGTH()<\/strong>\uff1a\u8fd4\u56de\u5b57\u4e32\u7684\u5b57\u7b26\u6578\u3002<\/li>\n<\/ul>\n<p>\u4f8b\u5982\uff1a<\/p>\n<pre><code>SELECT LENGTH('\u4f60\u597d\uff0c\u4e16\u754c');      -- \u8fd4\u56de 15\nSELECT CHAR_LENGTH('\u4f60\u597d\uff0c\u4e16\u754c');   -- \u8fd4\u56de 6\n<\/code><\/pre>\n<p>\u5728\u9019\u500b\u4f8b\u5b50\u4e2d\uff0cLENGTH()\u8fd4\u56de15\u662f\u56e0\u70ba\u6bcf\u500b\u4e2d\u6587\u5b57\u7b26\u4f54\u75283\u500b\u5b57\u7bc0\uff0c\u800cCHAR_LENGTH()\u5247\u8fd4\u56de6\uff0c\u56e0\u70ba\u5b83\u8a08\u7b97\u7684\u662f\u5b57\u7b26\u7684\u6578\u91cf\u3002<\/p>\n<h2 id=\"%e6%87%89%e7%94%a8%e5%a0%b4%e6%99%af-DtvNPgdmKC\">\u61c9\u7528\u5834\u666f<\/h2>\n<p>LENGTH()\u51fd\u6578\u5728\u8a31\u591a\u5834\u666f\u4e2d\u90fd\u975e\u5e38\u6709\u7528\uff0c\u4f8b\u5982\uff1a<\/p>\n<ul>\n<li>\u8cc7\u6599\u9a57\u8b49\uff1a\u53ef\u4ee5\u7528\u4f86\u6aa2\u67e5\u7528\u6236\u8f38\u5165\u7684\u8cc7\u6599\u662f\u5426\u7b26\u5408\u9577\u5ea6\u8981\u6c42\u3002<\/li>\n<li>\u8cc7\u6599\u6e05\u7406\uff1a\u5728\u8655\u7406\u8cc7\u6599\u6642\uff0c\u53ef\u4ee5\u904e\u6ffe\u6389\u9577\u5ea6\u4e0d\u7b26\u5408\u8981\u6c42\u7684\u8cc7\u6599\u3002<\/li>\n<li>\u5831\u544a\u751f\u6210\uff1a\u5728\u751f\u6210\u5831\u544a\u6642\uff0c\u53ef\u4ee5\u6839\u64da\u5b57\u4e32\u9577\u5ea6\u9032\u884c\u6392\u5e8f\u6216\u5206\u7d44\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b8%bd%e7%b5%90-DtvNPgdmKC\">\u7e3d\u7d50<\/h2>\n<p>LENGTH()\u51fd\u6578\u662fMySQL\u4e2d\u4e00\u500b\u975e\u5e38\u5be6\u7528\u7684\u5de5\u5177\uff0c\u80fd\u5920\u5e6b\u52a9\u958b\u767c\u8005\u548c\u8cc7\u6599\u5eab\u7ba1\u7406\u54e1\u6709\u6548\u5730\u8655\u7406\u5b57\u4e32\u8cc7\u6599\u3002\u7121\u8ad6\u662f\u5728\u8cc7\u6599\u9a57\u8b49\u3001\u6e05\u7406\u9084\u662f\u5831\u544a\u751f\u6210\u4e2d\uff0c\u4e86\u89e3\u5982\u4f55\u4f7f\u7528\u9019\u500b\u51fd\u6578\u90fd\u80fd\u63d0\u9ad8\u5de5\u4f5c\u6548\u7387\u3002\u5982\u679c\u60a8\u5c0d\u65bc\u8cc7\u6599\u5eab\u7ba1\u7406\u6709\u66f4\u6df1\u5165\u7684\u9700\u6c42\uff0c\u8003\u616e\u4f7f\u7528<a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a>\u4f86\u642d\u5efa\u60a8\u7684\u8cc7\u6599\u5eab\u74b0\u5883\uff0c\u4eab\u53d7\u66f4\u9ad8\u6548\u7684\u8cc7\u6599\u8655\u7406\u80fd\u529b\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4e86\u89e3MySQL\u6307\u4ee4LENGTH()\uff0c\u7528\u65bc\u8a08\u7b97\u5b57\u4e32\u7684\u5b57\u5143\u9577\u5ea6\uff0c\u5e6b\u52a9\u512a\u5316\u8cc7\u6599\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-78912","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/78912","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=78912"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/78912\/revisions"}],"predecessor-version":[{"id":78913,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/78912\/revisions\/78913"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=78912"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=78912"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=78912"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}