{"id":75888,"date":"2024-10-16T02:04:13","date_gmt":"2024-10-15T18:04:13","guid":{"rendered":"https:\/\/server.hk\/cnblog\/75888\/"},"modified":"2024-10-16T02:04:14","modified_gmt":"2024-10-15T18:04:14","slug":"mysql-%e5%a4%a7%e8%a1%a8%e9%87%8d%e8%a4%87%e5%ad%97%e6%ae%b5%e7%9a%84%e6%9f%a5%e8%a9%a2%e6%96%b9%e6%b3%95","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/75888\/","title":{"rendered":"MySQL \u5927\u8868\u91cd\u8907\u5b57\u6bb5\u7684\u67e5\u8a62\u65b9\u6cd5"},"content":{"rendered":"<h1 id=\"mysql-%e5%a4%a7%e8%a1%a8%e9%87%8d%e8%a4%87%e5%ad%97%e6%ae%b5%e7%9a%84%e6%9f%a5%e8%a9%a2%e6%96%b9%e6%b3%95-YuzgFkchqY\">MySQL \u5927\u8868\u91cd\u8907\u5b57\u6bb5\u7684\u67e5\u8a62\u65b9\u6cd5<\/h1>\n<p>\u5728\u6578\u64da\u5eab\u7ba1\u7406\u4e2d\uff0c\u91cd\u8907\u5b57\u6bb5\u7684\u67e5\u8a62\u662f\u4e00\u500b\u5e38\u898b\u7684\u9700\u6c42\uff0c\u5c24\u5176\u662f\u5728\u8655\u7406\u5927\u578b\u6578\u64da\u8868\u6642\u3002MySQL \u63d0\u4f9b\u4e86\u591a\u7a2e\u65b9\u6cd5\u4f86\u67e5\u8a62\u548c\u8655\u7406\u91cd\u8907\u6578\u64da\uff0c\u672c\u6587\u5c07\u4ecb\u7d39\u5e7e\u7a2e\u6709\u6548\u7684\u67e5\u8a62\u65b9\u6cd5\uff0c\u5e6b\u52a9\u60a8\u66f4\u597d\u5730\u7ba1\u7406\u6578\u64da\u3002<\/p>\n<h2 id=\"%e7%82%ba%e4%bb%80%e9%ba%bc%e9%9c%80%e8%a6%81%e6%9f%a5%e8%a9%a2%e9%87%8d%e8%a4%87%e5%ad%97%e6%ae%b5-YuzgFkchqY\">\u70ba\u4ec0\u9ebc\u9700\u8981\u67e5\u8a62\u91cd\u8907\u5b57\u6bb5<\/h2>\n<p>\u5728\u6578\u64da\u5eab\u4e2d\uff0c\u91cd\u8907\u6578\u64da\u53ef\u80fd\u6703\u5c0e\u81f4\u6578\u64da\u4e0d\u4e00\u81f4\u6027\uff0c\u5f71\u97ff\u67e5\u8a62\u6027\u80fd\uff0c\u751a\u81f3\u5f71\u97ff\u696d\u52d9\u6c7a\u7b56\u3002\u56e0\u6b64\uff0c\u5b9a\u671f\u6aa2\u67e5\u548c\u6e05\u7406\u91cd\u8907\u6578\u64da\u662f\u6578\u64da\u7ba1\u7406\u7684\u91cd\u8981\u90e8\u5206\u3002<\/p>\n<h2 id=\"%e6%9f%a5%e8%a9%a2%e9%87%8d%e8%a4%87%e5%ad%97%e6%ae%b5%e7%9a%84%e5%9f%ba%e6%9c%ac%e6%96%b9%e6%b3%95-YuzgFkchqY\">\u67e5\u8a62\u91cd\u8907\u5b57\u6bb5\u7684\u57fa\u672c\u65b9\u6cd5<\/h2>\n<p>\u5728 MySQL \u4e2d\uff0c\u67e5\u8a62\u91cd\u8907\u5b57\u6bb5\u901a\u5e38\u4f7f\u7528 <code>GROUP BY<\/code> \u548c <code>HAVING<\/code> \u5b50\u53e5\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u57fa\u672c\u7684\u67e5\u8a62\u793a\u4f8b\uff1a<\/p>\n<pre><code>SELECT column_name, COUNT(*) as count\nFROM table_name\nGROUP BY column_name\nHAVING COUNT(*) &gt; 1;<\/code><\/pre>\n<p>\u5728\u9019\u500b\u67e5\u8a62\u4e2d\uff0c<code>column_name<\/code> \u662f\u60a8\u8981\u6aa2\u67e5\u91cd\u8907\u7684\u5b57\u6bb5\uff0c<code>table_name<\/code> \u662f\u60a8\u7684\u6578\u64da\u8868\u540d\u7a31\u3002\u9019\u500b\u67e5\u8a62\u5c07\u8fd4\u56de\u6240\u6709\u91cd\u8907\u7684\u5b57\u6bb5\u53ca\u5176\u51fa\u73fe\u7684\u6b21\u6578\u3002<\/p>\n<h2 id=\"%e6%9f%a5%e8%a9%a2%e9%87%8d%e8%a4%87%e5%ad%97%e6%ae%b5%e7%9a%84%e9%80%b2%e9%9a%8e%e6%96%b9%e6%b3%95-YuzgFkchqY\">\u67e5\u8a62\u91cd\u8907\u5b57\u6bb5\u7684\u9032\u968e\u65b9\u6cd5<\/h2>\n<p>\u9664\u4e86\u57fa\u672c\u7684\u67e5\u8a62\u65b9\u6cd5\uff0c\u60a8\u9084\u53ef\u4ee5\u4f7f\u7528 <code>JOIN<\/code> \u4f86\u7372\u53d6\u66f4\u591a\u4fe1\u606f\u3002\u4f8b\u5982\uff0c\u5047\u8a2d\u60a8\u60f3\u8981\u67e5\u8a62\u91cd\u8907\u7684\u96fb\u5b50\u90f5\u4ef6\u5730\u5740\u53ca\u5176\u5c0d\u61c9\u7684\u7528\u6236 ID\uff0c\u60a8\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u67e5\u8a62\uff1a<\/p>\n<pre><code>SELECT a.user_id, a.email\nFROM users a\nJOIN (\n    SELECT email\n    FROM users\n    GROUP BY email\n    HAVING COUNT(*) &gt; 1\n) b ON a.email = b.email;<\/code><\/pre>\n<p>\u9019\u500b\u67e5\u8a62\u9996\u5148\u627e\u51fa\u6240\u6709\u91cd\u8907\u7684\u96fb\u5b50\u90f5\u4ef6\u5730\u5740\uff0c\u7136\u5f8c\u901a\u904e <code>JOIN<\/code> \u5c07\u5176\u8207\u539f\u59cb\u8868\u9023\u63a5\uff0c\u4ee5\u7372\u53d6\u5c0d\u61c9\u7684\u7528\u6236 ID\u3002<\/p>\n<h2 id=\"%e4%bd%bf%e7%94%a8%e5%ad%90%e6%9f%a5%e8%a9%a2%e6%9f%a5%e8%a9%a2%e9%87%8d%e8%a4%87%e5%ad%97%e6%ae%b5-YuzgFkchqY\">\u4f7f\u7528\u5b50\u67e5\u8a62\u67e5\u8a62\u91cd\u8907\u5b57\u6bb5<\/h2>\n<p>\u53e6\u4e00\u7a2e\u67e5\u8a62\u91cd\u8907\u5b57\u6bb5\u7684\u65b9\u6cd5\u662f\u4f7f\u7528\u5b50\u67e5\u8a62\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u793a\u4f8b\uff1a<\/p>\n<pre><code>SELECT *\nFROM users\nWHERE email IN (\n    SELECT email\n    FROM users\n    GROUP BY email\n    HAVING COUNT(*) &gt; 1\n);<\/code><\/pre>\n<p>\u9019\u500b\u67e5\u8a62\u5c07\u8fd4\u56de\u6240\u6709\u64c1\u6709\u91cd\u8907\u96fb\u5b50\u90f5\u4ef6\u5730\u5740\u7684\u7528\u6236\u7684\u5b8c\u6574\u4fe1\u606f\u3002<\/p>\n<h2 id=\"%e6%b8%85%e7%90%86%e9%87%8d%e8%a4%87%e6%95%b8%e6%93%9a-YuzgFkchqY\">\u6e05\u7406\u91cd\u8907\u6578\u64da<\/h2>\n<p>\u5728\u67e5\u8a62\u5230\u91cd\u8907\u6578\u64da\u5f8c\uff0c\u60a8\u53ef\u80fd\u9700\u8981\u9032\u884c\u6e05\u7406\u3002\u53ef\u4ee5\u4f7f\u7528 <code>DELETE<\/code> \u8a9e\u53e5\u4f86\u522a\u9664\u91cd\u8907\u7684\u8a18\u9304\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u793a\u4f8b\uff1a<\/p>\n<pre><code>DELETE a\nFROM users a\nJOIN users b \nON a.email = b.email\nWHERE a.id &gt; b.id;<\/code><\/pre>\n<p>\u9019\u500b\u67e5\u8a62\u5c07\u522a\u9664\u6240\u6709\u91cd\u8907\u7684\u96fb\u5b50\u90f5\u4ef6\u5730\u5740\uff0c\u53ea\u4fdd\u7559 ID \u6700\u5c0f\u7684\u90a3\u4e00\u689d\u8a18\u9304\u3002<\/p>\n<h2 id=\"%e7%b8%bd%e7%b5%90-YuzgFkchqY\">\u7e3d\u7d50<\/h2>\n<p>\u67e5\u8a62\u548c\u8655\u7406 MySQL \u4e2d\u7684\u5927\u8868\u91cd\u8907\u5b57\u6bb5\u662f\u4e00\u9805\u91cd\u8981\u7684\u6578\u64da\u7ba1\u7406\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\u6e05\u7406\u91cd\u8907\u6578\u64da\u3002\u9019\u4e0d\u50c5\u80fd\u63d0\u9ad8\u6578\u64da\u5eab\u7684\u6027\u80fd\uff0c\u9084\u80fd\u78ba\u4fdd\u6578\u64da\u7684\u4e00\u81f4\u6027\u548c\u6e96\u78ba\u6027\u3002<\/p>\n<p>\u5982\u679c\u60a8\u9700\u8981\u66f4\u9ad8\u6548\u7684\u6578\u64da\u7ba1\u7406\u89e3\u6c7a\u65b9\u6848\uff0c\u8003\u616e\u4f7f\u7528 <a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a> \u670d\u52d9\uff0c\u9019\u5c07\u70ba\u60a8\u7684\u6578\u64da\u5eab\u63d0\u4f9b\u7a69\u5b9a\u7684\u652f\u6301\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u63a2\u7d22 MySQL \u4e2d\u5927\u8868\u91cd\u8907\u5b57\u6bb5\u7684\u67e5\u8a62\u65b9\u6cd5\uff0c\u5b78\u7fd2\u9ad8\u6548\u8b58\u5225\u548c\u8655\u7406\u91cd\u8907\u6578\u64da\u7684\u6280\u5de7\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-75888","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/75888","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=75888"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/75888\/revisions"}],"predecessor-version":[{"id":75889,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/75888\/revisions\/75889"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=75888"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=75888"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=75888"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}