{"id":80892,"date":"2024-10-16T14:48:18","date_gmt":"2024-10-16T06:48:18","guid":{"rendered":"https:\/\/server.hk\/cnblog\/80892\/"},"modified":"2024-10-16T14:48:18","modified_gmt":"2024-10-16T06:48:18","slug":"mysql%e5%ad%97%e7%ac%a6%e4%b8%b2%e5%a6%82%e4%bd%95%e6%ad%a3%e7%a2%ba%e9%80%a3%e6%8e%a5%e5%87%bd%e6%95%b8","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/80892\/","title":{"rendered":"MySQL\u5b57\u7b26\u4e32\u5982\u4f55\u6b63\u78ba\u9023\u63a5\u51fd\u6578"},"content":{"rendered":"<h1 id=\"mysql%e5%ad%97%e7%ac%a6%e4%b8%b2%e5%a6%82%e4%bd%95%e6%ad%a3%e7%a2%ba%e9%80%a3%e6%8e%a5%e5%87%bd%e6%95%b8-QQOlyGrYXa\">MySQL\u5b57\u7b26\u4e32\u5982\u4f55\u6b63\u78ba\u9023\u63a5\u51fd\u6578<\/h1>\n<p>\u5728\u4f7f\u7528MySQL\u9032\u884c\u6578\u64da\u5eab\u64cd\u4f5c\u6642\uff0c\u5b57\u7b26\u4e32\u7684\u6b63\u78ba\u9023\u63a5\u662f\u975e\u5e38\u91cd\u8981\u7684\u3002\u7121\u8ad6\u662f\u5728\u67e5\u8a62\u3001\u63d2\u5165\u9084\u662f\u66f4\u65b0\u6578\u64da\u6642\uff0c\u6b63\u78ba\u7684\u5b57\u7b26\u4e32\u9023\u63a5\u90fd\u80fd\u78ba\u4fdd\u6578\u64da\u7684\u6e96\u78ba\u6027\u548c\u5b8c\u6574\u6027\u3002\u672c\u6587\u5c07\u63a2\u8a0eMySQL\u4e2d\u5b57\u7b26\u4e32\u9023\u63a5\u7684\u5e7e\u7a2e\u65b9\u6cd5\uff0c\u4e26\u63d0\u4f9b\u76f8\u61c9\u7684\u793a\u4f8b\u548c\u4ee3\u78bc\u7247\u6bb5\u3002<\/p>\n<h2 id=\"1-%e4%bd%bf%e7%94%a8-concat-%e5%87%bd%e6%95%b8-QQOlyGrYXa\">1. \u4f7f\u7528 CONCAT \u51fd\u6578<\/h2>\n<p>MySQL\u63d0\u4f9b\u4e86\u5167\u5efa\u7684 <code>CONCAT<\/code> \u51fd\u6578\u4f86\u9023\u63a5\u5b57\u7b26\u4e32\u3002\u9019\u500b\u51fd\u6578\u53ef\u4ee5\u63a5\u53d7\u591a\u500b\u53c3\u6578\uff0c\u4e26\u5c07\u5b83\u5011\u9023\u63a5\u6210\u4e00\u500b\u5b57\u7b26\u4e32\u3002\u4ee5\u4e0b\u662f\u4f7f\u7528 <code>CONCAT<\/code> \u51fd\u6578\u7684\u57fa\u672c\u8a9e\u6cd5\uff1a<\/p>\n<pre><code>SELECT CONCAT(string1, string2, ..., stringN) AS result;<\/code><\/pre>\n<p>\u4f8b\u5982\uff0c\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u540d\u70ba <code>users<\/code> \u7684\u8868\uff0c\u5305\u542b <code>first_name<\/code> \u548c <code>last_name<\/code> \u5169\u500b\u5b57\u6bb5\uff0c\u6211\u5011\u53ef\u4ee5\u9019\u6a23\u9023\u63a5\u5b83\u5011\uff1a<\/p>\n<pre><code>SELECT CONCAT(first_name, ' ', last_name) AS full_name FROM users;<\/code><\/pre>\n<h2 id=\"2-%e4%bd%bf%e7%94%a8-concat_ws-%e5%87%bd%e6%95%b8-QQOlyGrYXa\">2. \u4f7f\u7528 CONCAT_WS \u51fd\u6578<\/h2>\n<p>\u9664\u4e86 <code>CONCAT<\/code> \u51fd\u6578\uff0cMySQL\u9084\u63d0\u4f9b\u4e86 <code>CONCAT_WS<\/code> \u51fd\u6578\u3002\u9019\u500b\u51fd\u6578\u7684\u7279\u9ede\u662f\u53ef\u4ee5\u6307\u5b9a\u4e00\u500b\u5206\u9694\u7b26\uff0c\u4e26\u5c07\u591a\u500b\u5b57\u7b26\u4e32\u9023\u63a5\u5728\u4e00\u8d77\u3002\u5176\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre><code>SELECT CONCAT_WS(separator, string1, string2, ..., stringN) AS result;<\/code><\/pre>\n<p>\u4f8b\u5982\uff0c\u5982\u679c\u6211\u5011\u60f3\u7528\u9017\u865f\u4f86\u5206\u9694\u7528\u6236\u7684\u5168\u540d\uff0c\u53ef\u4ee5\u9019\u6a23\u5beb\uff1a<\/p>\n<pre><code>SELECT CONCAT_WS(', ', first_name, last_name) AS full_name FROM users;<\/code><\/pre>\n<h2 id=\"3-%e4%bd%bf%e7%94%a8-%e9%81%8b%e7%ae%97%e7%ac%a6-QQOlyGrYXa\">3. \u4f7f\u7528 || \u904b\u7b97\u7b26<\/h2>\n<p>\u5728\u67d0\u4e9b\u7248\u672c\u7684MySQL\u4e2d\uff0c\u9084\u53ef\u4ee5\u4f7f\u7528 <code>||<\/code> \u904b\u7b97\u7b26\u4f86\u9023\u63a5\u5b57\u7b26\u4e32\u3002\u4e0d\u904e\uff0c\u9019\u500b\u904b\u7b97\u7b26\u7684\u4f7f\u7528\u9700\u8981\u5728SQL\u6a21\u5f0f\u4e2d\u555f\u7528 <code>PIPES_AS_CONCAT<\/code>\u3002\u4ee5\u4e0b\u662f\u4f7f\u7528 <code>||<\/code> \u7684\u793a\u4f8b\uff1a<\/p>\n<pre><code>SELECT first_name || ' ' || last_name AS full_name FROM users;<\/code><\/pre>\n<p>\u9700\u8981\u6ce8\u610f\u7684\u662f\uff0c\u9019\u7a2e\u65b9\u6cd5\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\u53ef\u80fd\u6703\u5c0e\u81f4\u517c\u5bb9\u6027\u554f\u984c\uff0c\u56e0\u6b64\u5efa\u8b70\u4f7f\u7528 <code>CONCAT<\/code> \u6216 <code>CONCAT_WS<\/code> \u51fd\u6578\u3002<\/p>\n<h2 id=\"4-%e5%ad%97%e7%ac%a6%e4%b8%b2%e9%80%a3%e6%8e%a5%e7%9a%84%e6%b3%a8%e6%84%8f%e4%ba%8b%e9%a0%85-QQOlyGrYXa\">4. \u5b57\u7b26\u4e32\u9023\u63a5\u7684\u6ce8\u610f\u4e8b\u9805<\/h2>\n<p>\u5728\u9032\u884c\u5b57\u7b26\u4e32\u9023\u63a5\u6642\uff0c\u6709\u5e7e\u500b\u6ce8\u610f\u4e8b\u9805\u9700\u8981\u8003\u616e\uff1a<\/p>\n<ul>\n<li><strong>NULL \u503c\u8655\u7406\uff1a<\/strong>\u5982\u679c\u4efb\u4f55\u4e00\u500b\u53c3\u6578\u70ba <code>NULL<\/code>\uff0c\u5247 <code>CONCAT<\/code> \u51fd\u6578\u7684\u7d50\u679c\u5c07\u4e0d\u6703\u662f <code>NULL<\/code>\uff0c\u800c\u662f\u5c07 <code>NULL<\/code> \u7576\u4f5c\u7a7a\u5b57\u7b26\u4e32\u8655\u7406\u3002<\/li>\n<li><strong>\u5b57\u7b26\u96c6\u554f\u984c\uff1a<\/strong>\u5728\u9023\u63a5\u4e0d\u540c\u5b57\u7b26\u96c6\u7684\u5b57\u7b26\u4e32\u6642\uff0c\u53ef\u80fd\u6703\u51fa\u73fe\u5b57\u7b26\u96c6\u4e0d\u517c\u5bb9\u7684\u554f\u984c\uff0c\u9019\u53ef\u80fd\u5c0e\u81f4\u6578\u64da\u640d\u58de\u6216\u932f\u8aa4\u3002<\/li>\n<li><strong>\u6027\u80fd\u8003\u91cf\uff1a<\/strong>\u5728\u8655\u7406\u5927\u91cf\u6578\u64da\u6642\uff0c\u5b57\u7b26\u4e32\u9023\u63a5\u53ef\u80fd\u6703\u5f71\u97ff\u67e5\u8a62\u6027\u80fd\uff0c\u56e0\u6b64\u61c9\u8b39\u614e\u4f7f\u7528\u3002<\/li>\n<\/ul>\n<h2 id=\"5-%e5%af%a6%e9%9a%9b%e6%87%89%e7%94%a8%e7%a4%ba%e4%be%8b-QQOlyGrYXa\">5. \u5be6\u969b\u61c9\u7528\u793a\u4f8b<\/h2>\n<p>\u5728\u5be6\u969b\u61c9\u7528\u4e2d\uff0c\u5b57\u7b26\u4e32\u9023\u63a5\u5e38\u7528\u65bc\u751f\u6210\u5831\u544a\u3001\u986f\u793a\u7528\u6236\u4fe1\u606f\u7b49\u5834\u666f\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u5b8c\u6574\u7684\u67e5\u8a62\u793a\u4f8b\uff0c\u5c55\u793a\u5982\u4f55\u4f7f\u7528 <code>CONCAT<\/code> \u51fd\u6578\u4f86\u751f\u6210\u7528\u6236\u7684\u5168\u540d\uff1a<\/p>\n<pre><code>SELECT id, CONCAT(first_name, ' ', last_name) AS full_name FROM users WHERE active = 1;<\/code><\/pre>\n<p>\u9019\u500b\u67e5\u8a62\u5c07\u8fd4\u56de\u6240\u6709\u6d3b\u8e8d\u7528\u6236\u7684ID\u548c\u5168\u540d\uff0c\u65b9\u4fbf\u5f8c\u7e8c\u7684\u6578\u64da\u8655\u7406\u548c\u986f\u793a\u3002<\/p>\n<h2 id=\"%e7%b8%bd%e7%b5%90-QQOlyGrYXa\">\u7e3d\u7d50<\/h2>\n<p>\u5728MySQL\u4e2d\uff0c\u6b63\u78ba\u7684\u5b57\u7b26\u4e32\u9023\u63a5\u51fd\u6578\u5c0d\u65bc\u6578\u64da\u7684\u8655\u7406\u81f3\u95dc\u91cd\u8981\u3002\u901a\u904e\u4f7f\u7528 <code>CONCAT<\/code>\u3001<code>CONCAT_WS<\/code> \u548c <code>||<\/code> \u904b\u7b97\u7b26\uff0c\u6211\u5011\u53ef\u4ee5\u9748\u6d3b\u5730\u9023\u63a5\u5b57\u7b26\u4e32\uff0c\u6eff\u8db3\u4e0d\u540c\u7684\u9700\u6c42\u3002\u5728\u9032\u884c\u5b57\u7b26\u4e32\u9023\u63a5\u6642\uff0c\u9700\u6ce8\u610fNULL\u503c\u8655\u7406\u3001\u5b57\u7b26\u96c6\u554f\u984c\u53ca\u6027\u80fd\u8003\u91cf\u3002\u82e5\u60a8\u9700\u8981\u9032\u4e00\u6b65\u4e86\u89e3\u5982\u4f55\u5728 <a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a> \u4e0a\u904b\u884cMySQL\uff0c\u6216\u5c0b\u627e\u5408\u9069\u7684 <a href=\"https:\/\/server.hk\">\u9999\u6e2f\u4f3a\u670d\u5668<\/a> \u89e3\u6c7a\u65b9\u6848\uff0c\u8acb\u8a2a\u554f\u6211\u5011\u7684\u7db2\u7ad9\u4ee5\u7372\u53d6\u66f4\u591a\u4fe1\u606f\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4e86\u89e3\u5982\u4f55\u6b63\u78ba\u4f7f\u7528MySQL\u5b57\u7b26\u4e32\u9023\u63a5\u51fd\u6578\uff0c\u63d0\u5347\u6578\u64da\u8655\u7406\u6548\u7387\uff0c\u7c21\u5316\u67e5\u8a62\u8a9e\u53e5\uff0c\u589e\u5f37\u6578\u64da\u5eab\u64cd\u4f5c\u80fd\u529b\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-80892","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/80892","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=80892"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/80892\/revisions"}],"predecessor-version":[{"id":80893,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/80892\/revisions\/80893"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=80892"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=80892"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=80892"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}