{"id":75830,"date":"2024-10-16T01:35:17","date_gmt":"2024-10-15T17:35:17","guid":{"rendered":"https:\/\/server.hk\/cnblog\/75830\/"},"modified":"2024-10-16T01:35:17","modified_gmt":"2024-10-15T17:35:17","slug":"mysql-%e6%9f%a5%e8%a9%a2%e9%87%8d%e8%a4%87%e8%a8%98%e9%8c%84%e7%9a%84%e6%96%b9%e6%b3%95","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/75830\/","title":{"rendered":"MySQL \u67e5\u8a62\u91cd\u8907\u8a18\u9304\u7684\u65b9\u6cd5"},"content":{"rendered":"<h1 id=\"mysql-%e6%9f%a5%e8%a9%a2%e9%87%8d%e8%a4%87%e8%a8%98%e9%8c%84%e7%9a%84%e6%96%b9%e6%b3%95-nhhOUDlRWQ\">MySQL \u67e5\u8a62\u91cd\u8907\u8a18\u9304\u7684\u65b9\u6cd5<\/h1>\n<p>\u5728\u6578\u64da\u5eab\u7ba1\u7406\u4e2d\uff0c\u91cd\u8907\u8a18\u9304\u662f\u4e00\u500b\u5e38\u898b\u7684\u554f\u984c\uff0c\u7279\u5225\u662f\u5728\u8655\u7406\u5927\u91cf\u6578\u64da\u6642\u3002MySQL \u4f5c\u70ba\u4e00\u500b\u6d41\u884c\u7684\u95dc\u806f\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\uff0c\u63d0\u4f9b\u4e86\u591a\u7a2e\u65b9\u6cd5\u4f86\u67e5\u8a62\u548c\u8655\u7406\u91cd\u8907\u8a18\u9304\u3002\u672c\u6587\u5c07\u63a2\u8a0e\u5e7e\u7a2e\u6709\u6548\u7684\u67e5\u8a62\u91cd\u8907\u8a18\u9304\u7684\u65b9\u6cd5\uff0c\u5e6b\u52a9\u7528\u6236\u66f4\u597d\u5730\u7ba1\u7406\u6578\u64da\u3002<\/p>\n<h2 id=\"%e4%bb%80%e9%ba%bc%e6%98%af%e9%87%8d%e8%a4%87%e8%a8%98%e9%8c%84%ef%bc%9f-nhhOUDlRWQ\">\u4ec0\u9ebc\u662f\u91cd\u8907\u8a18\u9304\uff1f<\/h2>\n<p>\u91cd\u8907\u8a18\u9304\u662f\u6307\u5728\u6578\u64da\u8868\u4e2d\u5b58\u5728\u591a\u689d\u76f8\u540c\u6216\u76f8\u4f3c\u7684\u8a18\u9304\u3002\u9019\u4e9b\u91cd\u8907\u7684\u6578\u64da\u53ef\u80fd\u6703\u5c0e\u81f4\u6578\u64da\u4e0d\u4e00\u81f4\uff0c\u5f71\u97ff\u67e5\u8a62\u6548\u7387\uff0c\u751a\u81f3\u5f71\u97ff\u696d\u52d9\u6c7a\u7b56\u3002\u56e0\u6b64\uff0c\u8b58\u5225\u548c\u8655\u7406\u91cd\u8907\u8a18\u9304\u662f\u6578\u64da\u7ba1\u7406\u4e2d\u7684\u4e00\u500b\u91cd\u8981\u6b65\u9a5f\u3002<\/p>\n<h2 id=\"%e6%9f%a5%e8%a9%a2%e9%87%8d%e8%a4%87%e8%a8%98%e9%8c%84%e7%9a%84%e6%96%b9%e6%b3%95-nhhOUDlRWQ\">\u67e5\u8a62\u91cd\u8907\u8a18\u9304\u7684\u65b9\u6cd5<\/h2>\n<h3 id=\"%e4%bd%bf%e7%94%a8-group-by-%e5%92%8c-having-%e5%ad%90%e5%8f%a5-nhhOUDlRWQ\">\u4f7f\u7528 GROUP BY \u548c HAVING \u5b50\u53e5<\/h3>\n<p>\u6700\u5e38\u898b\u7684\u65b9\u6cd5\u662f\u4f7f\u7528 <code>GROUP BY<\/code> \u548c <code>HAVING<\/code> \u5b50\u53e5\u3002\u9019\u7a2e\u65b9\u6cd5\u53ef\u4ee5\u5e6b\u52a9\u6211\u5011\u627e\u51fa\u5728\u7279\u5b9a\u5217\u4e2d\u51fa\u73fe\u591a\u6b21\u7684\u8a18\u9304\u3002<\/p>\n<pre><code>SELECT column_name, COUNT(*)\nFROM table_name\nGROUP BY column_name\nHAVING COUNT(*) &gt; 1;<\/code><\/pre>\n<p>\u5728\u9019\u6bb5 SQL \u67e5\u8a62\u4e2d\uff0c<code>column_name<\/code> \u662f\u4f60\u60f3\u8981\u6aa2\u67e5\u91cd\u8907\u7684\u5217\u540d\uff0c<code>table_name<\/code> \u662f\u4f60\u7684\u6578\u64da\u8868\u540d\u3002\u9019\u500b\u67e5\u8a62\u5c07\u8fd4\u56de\u6240\u6709\u91cd\u8907\u7684\u8a18\u9304\u53ca\u5176\u51fa\u73fe\u7684\u6b21\u6578\u3002<\/p>\n<h3 id=\"%e4%bd%bf%e7%94%a8-distinct-%e5%92%8c-join-nhhOUDlRWQ\">\u4f7f\u7528 DISTINCT \u548c JOIN<\/h3>\n<p>\u53e6\u4e00\u7a2e\u65b9\u6cd5\u662f\u4f7f\u7528 <code>DISTINCT<\/code> \u548c <code>JOIN<\/code>\u3002\u9019\u7a2e\u65b9\u6cd5\u53ef\u4ee5\u5e6b\u52a9\u6211\u5011\u7372\u53d6\u552f\u4e00\u7684\u8a18\u9304\uff0c\u4e26\u8207\u539f\u59cb\u8868\u9032\u884c\u6bd4\u8f03\u3002<\/p>\n<pre><code>SELECT a.*\nFROM table_name a\nJOIN (SELECT column_name\n      FROM table_name\n      GROUP BY column_name\n      HAVING COUNT(*) &gt; 1) b\nON a.column_name = b.column_name;<\/code><\/pre>\n<p>\u9019\u6bb5\u67e5\u8a62\u5c07\u8fd4\u56de\u6240\u6709\u91cd\u8907\u7684\u8a18\u9304\uff0c\u4e26\u4e14\u53ef\u4ee5\u986f\u793a\u51fa\u5b8c\u6574\u7684\u884c\u6578\u64da\u3002<\/p>\n<h3 id=\"%e4%bd%bf%e7%94%a8%e5%ad%90%e6%9f%a5%e8%a9%a2-nhhOUDlRWQ\">\u4f7f\u7528\u5b50\u67e5\u8a62<\/h3>\n<p>\u5b50\u67e5\u8a62\u4e5f\u662f\u4e00\u7a2e\u6709\u6548\u7684\u65b9\u6cd5\uff0c\u53ef\u4ee5\u7528\u4f86\u67e5\u8a62\u91cd\u8907\u8a18\u9304\u3002<\/p>\n<pre><code>SELECT *\nFROM table_name\nWHERE column_name IN (SELECT column_name\n                      FROM table_name\n                      GROUP BY column_name\n                      HAVING COUNT(*) &gt; 1);<\/code><\/pre>\n<p>\u9019\u500b\u67e5\u8a62\u5c07\u8fd4\u56de\u6240\u6709\u5728\u6307\u5b9a\u5217\u4e2d\u51fa\u73fe\u591a\u6b21\u7684\u5b8c\u6574\u8a18\u9304\u3002<\/p>\n<h2 id=\"%e8%99%95%e7%90%86%e9%87%8d%e8%a4%87%e8%a8%98%e9%8c%84-nhhOUDlRWQ\">\u8655\u7406\u91cd\u8907\u8a18\u9304<\/h2>\n<p>\u5728\u67e5\u8a62\u5230\u91cd\u8907\u8a18\u9304\u5f8c\uff0c\u63a5\u4e0b\u4f86\u7684\u6b65\u9a5f\u662f\u5982\u4f55\u8655\u7406\u9019\u4e9b\u91cd\u8907\u7684\u6578\u64da\u3002\u5e38\u898b\u7684\u8655\u7406\u65b9\u6cd5\u5305\u62ec\uff1a<\/p>\n<ul>\n<li><strong>\u522a\u9664\u91cd\u8907\u8a18\u9304\uff1a<\/strong>\u53ef\u4ee5\u4f7f\u7528 <code>DELETE<\/code> \u8a9e\u53e5\u522a\u9664\u91cd\u8907\u7684\u884c\u3002<\/li>\n<li><strong>\u5408\u4f75\u6578\u64da\uff1a<\/strong>\u5982\u679c\u91cd\u8907\u7684\u8a18\u9304\u4e2d\u6709\u4e0d\u540c\u7684\u6578\u64da\uff0c\u53ef\u4ee5\u8003\u616e\u5408\u4f75\u9019\u4e9b\u6578\u64da\u3002<\/li>\n<li><strong>\u6a19\u8a18\u91cd\u8907\uff1a<\/strong>\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\uff0c\u53ef\u80fd\u9700\u8981\u6a19\u8a18\u91cd\u8907\u7684\u8a18\u9304\u4ee5\u4fbf\u5f8c\u7e8c\u8655\u7406\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b8%bd%e7%b5%90-nhhOUDlRWQ\">\u7e3d\u7d50<\/h2>\n<p>\u67e5\u8a62\u548c\u8655\u7406\u91cd\u8907\u8a18\u9304\u662f\u6578\u64da\u5eab\u7ba1\u7406\u4e2d\u7684\u4e00\u500b\u91cd\u8981\u4efb\u52d9\u3002\u901a\u904e\u4f7f\u7528 <code>GROUP BY<\/code>\u3001<code>JOIN<\/code> \u548c\u5b50\u67e5\u8a62\u7b49\u65b9\u6cd5\uff0c\u60a8\u53ef\u4ee5\u6709\u6548\u5730\u8b58\u5225\u548c\u7ba1\u7406\u91cd\u8907\u6578\u64da\u3002\u9019\u4e0d\u50c5\u80fd\u63d0\u9ad8\u6578\u64da\u7684\u6e96\u78ba\u6027\uff0c\u9084\u80fd\u63d0\u5347\u67e5\u8a62\u6548\u7387\u3002\u5c0d\u65bc\u9700\u8981\u9ad8\u6548\u6578\u64da\u7ba1\u7406\u7684\u7528\u6236\uff0c\u9078\u64c7\u5408\u9069\u7684 <a href=\"https:\/\/server.hk\">VPS<\/a> \u89e3\u6c7a\u65b9\u6848\u5c07\u6709\u52a9\u65bc\u66f4\u597d\u5730\u904b\u884c MySQL \u6578\u64da\u5eab\uff0c\u78ba\u4fdd\u6578\u64da\u7684\u5b89\u5168\u548c\u7a69\u5b9a\u6027\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4e86\u89e3\u5982\u4f55\u5728 MySQL \u4e2d\u67e5\u8a62\u91cd\u8907\u8a18\u9304\uff0c\u638c\u63e1\u6709\u6548\u7684 SQL \u8a9e\u53e5\u548c\u6280\u5de7\uff0c\u63d0\u5347\u6578\u64da\u7ba1\u7406\u6548\u7387\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-75830","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/75830","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=75830"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/75830\/revisions"}],"predecessor-version":[{"id":75831,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/75830\/revisions\/75831"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=75830"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=75830"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=75830"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}