{"id":172823,"date":"2024-11-07T15:21:18","date_gmt":"2024-11-07T07:21:18","guid":{"rendered":"https:\/\/server.hk\/cnblog\/172823\/"},"modified":"2024-11-07T15:21:19","modified_gmt":"2024-11-07T07:21:19","slug":"%e5%a6%82%e4%bd%95%e6%9f%a5%e8%a9%a2%e6%95%b8%e6%93%9a%e5%ba%ab%e4%b8%ad%e7%9a%84%e9%87%8d%e8%a4%87%e8%a8%98%e9%8c%84%ef%bc%9f-%e6%9f%a5%e8%a9%a2%e6%95%b8%e6%93%9a%e5%ba%ab%e4%b8%ad%e7%9a%84%e9%87%8d","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/172823\/","title":{"rendered":"\u5982\u4f55\u67e5\u8a62\u6578\u64da\u5eab\u4e2d\u7684\u91cd\u8907\u8a18\u9304\uff1f (\u67e5\u8a62\u6578\u64da\u5eab\u4e2d\u7684\u91cd\u8907\u8a18\u9304)"},"content":{"rendered":"<h1 id=\"%e5%a6%82%e4%bd%95%e6%9f%a5%e8%a9%a2%e6%95%b8%e6%93%9a%e5%ba%ab%e4%b8%ad%e7%9a%84%e9%87%8d%e8%a4%87%e8%a8%98%e9%8c%84%ef%bc%9f-mlUJuUGrMH\">\u5982\u4f55\u67e5\u8a62\u6578\u64da\u5eab\u4e2d\u7684\u91cd\u8907\u8a18\u9304\uff1f<\/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\u3002\u91cd\u8907\u8a18\u9304\u4e0d\u50c5\u6703\u5f71\u97ff\u6578\u64da\u7684\u6e96\u78ba\u6027\uff0c\u9084\u53ef\u80fd\u5c0e\u81f4\u6027\u80fd\u554f\u984c\u3002\u56e0\u6b64\uff0c\u4e86\u89e3\u5982\u4f55\u67e5\u8a62\u6578\u64da\u5eab\u4e2d\u7684\u91cd\u8907\u8a18\u9304\u662f\u6bcf\u4f4d\u6578\u64da\u5eab\u7ba1\u7406\u54e1\u5fc5\u9808\u638c\u63e1\u7684\u6280\u80fd\u3002\u672c\u6587\u5c07\u4ecb\u7d39\u5e7e\u7a2e\u67e5\u8a62\u91cd\u8907\u8a18\u9304\u7684\u65b9\u6cd5\uff0c\u4e26\u63d0\u4f9b\u76f8\u61c9\u7684 SQL \u793a\u4f8b\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-mlUJuUGrMH\">\u4ec0\u9ebc\u662f\u91cd\u8907\u8a18\u9304\uff1f<\/h2>\n<p>\u91cd\u8907\u8a18\u9304\u662f\u6307\u5728\u6578\u64da\u5eab\u8868\u4e2d\u5b58\u5728\u591a\u689d\u76f8\u540c\u6216\u76f8\u4f3c\u7684\u8a18\u9304\u3002\u9019\u4e9b\u8a18\u9304\u53ef\u80fd\u662f\u7531\u65bc\u6578\u64da\u8f38\u5165\u932f\u8aa4\u3001\u6578\u64da\u5c0e\u5165\u904e\u7a0b\u4e2d\u7684\u554f\u984c\u6216\u5176\u4ed6\u539f\u56e0\u9020\u6210\u7684\u3002\u91cd\u8907\u8a18\u9304\u6703\u5c0e\u81f4\u6578\u64da\u5197\u9918\uff0c\u5f71\u97ff\u67e5\u8a62\u6548\u7387\uff0c\u4e26\u53ef\u80fd\u5c0e\u81f4\u932f\u8aa4\u7684\u5206\u6790\u7d50\u679c\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-mlUJuUGrMH\">\u67e5\u8a62\u91cd\u8907\u8a18\u9304\u7684\u65b9\u6cd5<\/h2>\n<p>\u67e5\u8a62\u91cd\u8907\u8a18\u9304\u7684\u4e3b\u8981\u65b9\u6cd5\u662f\u4f7f\u7528 SQL \u8a9e\u53e5\u4e2d\u7684 <code>GROUP BY<\/code> \u548c <code>HAVING<\/code> \u5b50\u53e5\u3002\u4ee5\u4e0b\u662f\u4e00\u4e9b\u5e38\u898b\u7684\u67e5\u8a62\u793a\u4f8b\uff1a<\/p>\n<h3 id=\"%e4%bd%bf%e7%94%a8-group-by-%e5%92%8c-having-mlUJuUGrMH\">\u4f7f\u7528 GROUP BY \u548c HAVING<\/h3>\n<p>\u9019\u662f\u67e5\u8a62\u91cd\u8907\u8a18\u9304\u6700\u5e38\u7528\u7684\u65b9\u6cd5\u3002\u901a\u904e <code>GROUP BY<\/code> \u5c07\u8a18\u9304\u5206\u7d44\uff0c\u7136\u5f8c\u4f7f\u7528 <code>HAVING<\/code> \u4f86\u7be9\u9078\u51fa\u51fa\u73fe\u6b21\u6578\u5927\u65bc 1 \u7684\u8a18\u9304\u3002<\/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\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=\"%e6%9f%a5%e8%a9%a2%e5%a4%9a%e5%80%8b%e5%88%97%e7%9a%84%e9%87%8d%e8%a4%87%e8%a8%98%e9%8c%84-mlUJuUGrMH\">\u67e5\u8a62\u591a\u500b\u5217\u7684\u91cd\u8907\u8a18\u9304<\/h3>\n<p>\u5982\u679c\u4f60\u9700\u8981\u67e5\u8a62\u591a\u500b\u5217\u7684\u91cd\u8907\u8a18\u9304\uff0c\u53ef\u4ee5\u5728 <code>GROUP BY<\/code> \u4e2d\u5217\u51fa\u591a\u500b\u5217\u540d\uff1a<\/p>\n<pre><code>SELECT column1, column2, COUNT(*) as count\nFROM table_name\nGROUP BY column1, column2\nHAVING COUNT(*) &gt; 1;<\/code><\/pre>\n<p>\u9019\u6a23\u7684\u67e5\u8a62\u5c07\u8fd4\u56de\u5728 <code>column1<\/code> \u548c <code>column2<\/code> \u4e2d\u90fd\u5b58\u5728\u91cd\u8907\u7684\u8a18\u9304\u3002<\/p>\n<h3 id=\"%e4%bd%bf%e7%94%a8-distinct-%e5%92%8c-join-mlUJuUGrMH\">\u4f7f\u7528 DISTINCT \u548c JOIN<\/h3>\n<p>\u53e6\u4e00\u7a2e\u67e5\u8a62\u91cd\u8907\u8a18\u9304\u7684\u65b9\u6cd5\u662f\u4f7f\u7528 <code>DISTINCT<\/code> \u548c <code>JOIN<\/code>\u3002\u9019\u7a2e\u65b9\u6cd5\u53ef\u4ee5\u7528\u4f86\u67e5\u8a62\u91cd\u8907\u8a18\u9304\u7684\u8a73\u7d30\u4fe1\u606f\uff1a<\/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\u500b\u67e5\u8a62\u5c07\u8fd4\u56de\u6240\u6709\u91cd\u8907\u8a18\u9304\u7684\u8a73\u7d30\u4fe1\u606f\uff0c\u800c\u4e0d\u50c5\u50c5\u662f\u91cd\u8907\u7684\u5217\u503c\u3002<\/p>\n<h2 id=\"%e5%a6%82%e4%bd%95%e8%99%95%e7%90%86%e9%87%8d%e8%a4%87%e8%a8%98%e9%8c%84-mlUJuUGrMH\">\u5982\u4f55\u8655\u7406\u91cd\u8907\u8a18\u9304<\/h2>\n<p>\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\u8a18\u9304\uff0c\u901a\u5e38\u9700\u8981\u5148\u78ba\u5b9a\u4fdd\u7559\u54ea\u4e00\u689d\u8a18\u9304\u3002<\/li>\n<li><strong>\u5408\u4f75\u91cd\u8907\u8a18\u9304\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\u8a18\u9304\u3002<\/li>\n<li><strong>\u66f4\u65b0\u6578\u64da\uff1a<\/strong>\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\uff0c\u53ef\u80fd\u9700\u8981\u66f4\u65b0\u91cd\u8907\u8a18\u9304\u4e2d\u7684\u67d0\u4e9b\u5b57\u6bb5\uff0c\u4ee5\u78ba\u4fdd\u6578\u64da\u7684\u4e00\u81f4\u6027\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b8%bd%e7%b5%90-mlUJuUGrMH\">\u7e3d\u7d50<\/h2>\n<p>\u67e5\u8a62\u6578\u64da\u5eab\u4e2d\u7684\u91cd\u8907\u8a18\u9304\u662f\u4e00\u9805\u91cd\u8981\u7684\u6578\u64da\u7ba1\u7406\u4efb\u52d9\uff0c\u80fd\u5920\u5e6b\u52a9\u78ba\u4fdd\u6578\u64da\u7684\u6e96\u78ba\u6027\u548c\u5b8c\u6574\u6027\u3002\u901a\u904e\u4f7f\u7528 SQL \u7684 <code>GROUP BY<\/code> \u548c <code>HAVING<\/code> \u5b50\u53e5\uff0c\u6578\u64da\u5eab\u7ba1\u7406\u54e1\u53ef\u4ee5\u8f15\u9b06\u8b58\u5225\u548c\u8655\u7406\u91cd\u8907\u8a18\u9304\u3002\u5c0d\u65bc\u9700\u8981\u9ad8\u6548\u6578\u64da\u8655\u7406\u7684\u4f01\u696d\uff0c\u9078\u64c7\u5408\u9069\u7684 <a href=\"https:\/\/server.hk\">VPS<\/a> \u89e3\u6c7a\u65b9\u6848\u53ef\u4ee5\u63d0\u4f9b\u66f4\u597d\u7684\u6027\u80fd\u548c\u7a69\u5b9a\u6027\uff0c\u9032\u4e00\u6b65\u63d0\u5347\u6578\u64da\u7ba1\u7406\u7684\u6548\u7387\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u5b78\u7fd2\u5982\u4f55\u5728\u6578\u64da\u5eab\u4e2d\u67e5\u8a62\u91cd\u8907\u8a18\u9304\uff0c\u638c\u63e1\u6709\u6548\u7684SQL\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-172823","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/172823","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=172823"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/172823\/revisions"}],"predecessor-version":[{"id":172824,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/172823\/revisions\/172824"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=172823"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=172823"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=172823"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}