{"id":37708,"date":"2023-07-09T11:06:21","date_gmt":"2023-07-09T03:06:21","guid":{"rendered":"https:\/\/docs.pingcode.com\/?p=37708"},"modified":"2023-07-31T00:35:32","modified_gmt":"2023-07-30T16:35:32","slug":"%e6%80%8e%e6%a0%b7%e7%94%a8sql%e8%af%ad%e5%8f%a5%e5%ae%9e%e7%8e%b0%e6%9f%a5%e6%89%be%e4%b8%80%e5%88%97%e4%b8%ad%e7%ac%acn%e5%a4%a7%e5%80%bc","status":"publish","type":"post","link":"https:\/\/docs.pingcode.com\/ask\/37708.html","title":{"rendered":"\u600e\u6837\u7528SQL\u8bed\u53e5\u5b9e\u73b0\u67e5\u627e\u4e00\u5217\u4e2d\u7b2cN\u5927\u503c"},"content":{"rendered":"<blockquote class=\"wp-block-quote\">\n<p>\u4f7f\u7528SQL\u8bed\u53e5\u6765\u67e5\u627e\u4e00\u5217\u4e2d\u7684\u7b2cN\u5927\u503c\u4e3b\u8981\u6db5\u76d6\u4ee5\u4e0b\u51e0\u4e2a\u90e8\u5206\uff1a1. \u5982\u4f55\u4f7f\u7528ORDER BY\u8bed\u53e5\u548cLIMIT\u8bed\u53e5\u67e5\u627e\u7b2cN\u5927\u503c\uff1b2. \u4f7f\u7528\u5b50\u67e5\u8be2\u67e5\u627e\u7b2cN\u5927\u503c\uff1b3. \u4f7f\u7528\u6392\u540d\u51fd\u6570\u67e5\u627e\u7b2cN\u5927\u503c\u3002\u8fd9\u4e09\u79cd\u65b9\u6cd5\u5404\u6709\u5229\u5f0a\uff0c\u4f46\u53ef\u4ee5\u6839\u636e\u4e0d\u540c\u7684\u9700\u6c42\u548c\u73af\u5883\u6765\u9009\u62e9\u4f7f\u7528\u3002<\/p>\n<\/blockquote>\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full\"><img fetchpriority=\"high\" alt=\"\" class=\"wp-image-37707\" decoding=\"async\" height=\"300\" sizes=\"(max-width: 484px) 100vw, 484px\" src=\"https:\/\/cdn-docs.pingcode.com\/wp-content\/uploads\/2023\/07\/\u6dfb\u52a0\u6807\u9898-11.png?x-oss-process=image\/auto-orient,1\/format,webp\" srcset=\"https:\/\/cdn-docs.pingcode.com\/wp-content\/uploads\/2023\/07\/\u6dfb\u52a0\u6807\u9898-11.png?x-oss-process=image\/auto-orient,1\/format,webp 484w, https:\/\/cdn-docs.pingcode.com\/wp-content\/uploads\/2023\/07\/\u6dfb\u52a0\u6807\u9898-11-300x186.png 300w\" width=\"484\"\/><\/figure>\n<\/div>\n<h2 class=\"wp-block-heading\"><strong>\u600e\u6837\u7528SQL\u8bed\u53e5\u5b9e\u73b0\u67e5\u627e\u4e00\u5217\u4e2d\u7b2cN\u5927\u503c<\/strong><\/h2>\n<p>\u5728SQL\u4e2d\uff0c\u67e5\u627e\u4e00\u5217\u4e2d\u7684\u7b2cN\u5927\u503c\u53ef\u80fd\u6709\u591a\u79cd\u65b9\u6cd5\u3002\u6211\u4eec\u53ef\u4ee5\u4f7f\u7528ORDER BY\u548cLIMIT\u8bed\u53e5\uff0c\u4e5f\u53ef\u4ee5\u4f7f\u7528\u5b50\u67e5\u8be2\uff0c\u8fd8\u53ef\u4ee5\u4f7f\u7528\u6392\u540d\u51fd\u6570\u3002\u4e0b\u9762\u5c06\u4f1a\u8be6\u7ec6\u4ecb\u7ecd\u8fd9\u4e09\u79cd\u65b9\u6cd5\u3002<\/p>\n<p><strong>1<\/strong><strong>\u3001\u4f7f\u7528ORDER BY\u8bed\u53e5\u548cLIMIT\u8bed\u53e5\u67e5\u627e\u7b2cN\u5927\u503c<\/strong><\/p>\n<p>\u6211\u4eec\u53ef\u4ee5\u5229\u7528SQL\u7684ORDER BY\u8bed\u53e5\u5c06\u6570\u636e\u6309\u7167\u67d0\u5217\u8fdb\u884c\u964d\u5e8f\u6392\u5e8f\uff0c\u7136\u540e\u4f7f\u7528LIMIT\u8bed\u53e5\u6765\u53d6\u7b2cN\u884c\u7684\u6570\u636e\u3002<\/p>\n<p>\u793a\u4f8b\u4ee3\u7801\uff1a<\/p>\n<p>\u201c`sql<\/p>\n<p>SELECT column_name<\/p>\n<p>FROM table_name<\/p>\n<p>ORDER BY column_name DESC<\/p>\n<p>LIMIT N-1,1;<\/p>\n<p>\u201c<\/p>\n<p>\u5728\u8fd9\u91cc\uff0ccolumn_name\u662f\u4f60\u8981\u67e5\u627e\u7684\u5217\u540d\uff0ctable_name\u662f\u8868\u540d\uff0cN\u662f\u4f60\u8981\u67e5\u627e\u7684\u7b2cN\u5927\u503c\u3002<\/p>\n<p><strong>2<\/strong><strong>\u3001\u4f7f\u7528\u5b50\u67e5\u8be2\u67e5\u627e\u7b2cN\u5927\u503c<\/strong><\/p>\n<p>\u6211\u4eec\u4e5f\u53ef\u4ee5\u901a\u8fc7\u5b50\u67e5\u8be2\u7684\u65b9\u5f0f\u6765\u67e5\u627e\u7b2cN\u5927\u7684\u503c\u3002<\/p>\n<p>\u793a\u4f8b\u4ee3\u7801\uff1a<\/p>\n<p>\u201c`sql<\/p>\n<p>SELECT column_name<\/p>\n<p>FROM table_name t1<\/p>\n<p>WHERE (N \u2013 1) = (SELECT COUNT(DISTINCT column_name)<\/p>\n<p>FROM table_name t2<\/p>\n<p>WHERE t2.column_name &gt; t1.column_name)<\/p>\n<p>\u201c`<\/p>\n<p>\u5728\u8fd9\u91cc\uff0c\u6211\u4eec\u9996\u5148\u5bf9\u5217\u540d\u8fdb\u884c\u4e86\u5b50\u67e5\u8be2\uff0c\u5e76\u4e14\u5c06\u5f97\u5230\u7684\u7ed3\u679c\u96c6\u7684\u884c\u6570\u4e0eN \u2013 1\u8fdb\u884c\u6bd4\u8f83\u3002<\/p>\n<p><strong>3<\/strong><strong>\u3001\u4f7f\u7528\u6392\u540d\u51fd\u6570\u67e5\u627e\u7b2cN\u5927\u503c<\/strong><\/p>\n<p>SQL\u4e2d\u7684RANK()\u3001DENSE_RANK()\u6216ROW_NUMBER()\u7b49\u51fd\u6570\u4e5f\u53ef\u4ee5\u5e2e\u52a9\u6211\u4eec\u627e\u5230\u7b2cN\u5927\u7684\u503c\u3002<\/p>\n<p>\u793a\u4f8b\u4ee3\u7801\uff1a<\/p>\n<p>\u201c`sql<\/p>\n<p>SELECT column_name<\/p>\n<p>FROM (<\/p>\n<p>SELECT column_name, DENSE_RANK() OVER (ORDER BY column_name DESC) as ranking<\/p>\n<p>FROM table_name<\/p>\n<p>) t<\/p>\n<p>WHERE ranking = N<\/p>\n<p>\u201c`<\/p>\n<p>\u5728\u8fd9\u91cc\uff0c\u6211\u4eec\u4f7f\u7528\u4e86DENSE_RANK()\u51fd\u6570\u6765\u751f\u6210\u4e00\u4e2a\u6392\u540d\uff0c\u7136\u540e\u4ece\u4e2d\u9009\u51fa\u6392\u540d\u4e3aN\u7684\u884c\u3002<\/p>\n<p>\u4ee5\u4e0a\u5c31\u662f\u4e09\u79cd\u5728SQL\u4e2d\u67e5\u627e\u4e00\u5217\u4e2d\u7b2cN\u5927\u503c\u7684\u65b9\u6cd5\uff0c\u53ef\u4ee5\u6839\u636e\u5177\u4f53\u7684\u9700\u6c42\u548c\u73af\u5883\u6765\u9009\u62e9\u9002\u5408\u7684\u65b9\u6cd5\u3002<\/p>\n<h2 class=\"wp-block-heading\"><strong>\u5ef6\u4f38\u9605\u8bfb<\/strong><\/h2>\n<p>\u300aSQL\u5fc5\u77e5\u5fc5\u4f1a\u300b\u662f\u4e00\u672c\u4e13\u95e8\u4e3a\u521d\u5b66\u8005\u7f16\u5199\u7684SQL\u57fa\u7840\u6559\u7a0b\u3002\u5168\u4e66\u4ece\u5b9e\u9645\u5e94\u7528\u51fa\u53d1\uff0c\u901a\u8fc7\u5927\u91cf\u7684\u5b9e\u4f8b\u548c\u56fe\u793a\uff0c\u8be6\u7ec6\u89e3\u91ca\u4e86\u5982\u4f55\u521b\u5efa\u6570\u636e\u5e93\u3001\u5982\u4f55\u8fdb\u884c\u6570\u636e\u67e5\u8be2\u3001\u5982\u4f55\u66f4\u65b0\u548c\u5220\u9664\u6570\u636e\u7b49\u57fa\u672c\u64cd\u4f5c\uff0c\u4ee5\u53ca\u5982\u4f55\u4f7f\u7528\u51fd\u6570\u3001\u5982\u4f55\u521b\u5efa\u89c6\u56fe\u3001\u5982\u4f55\u5904\u7406\u6587\u672c\u548c\u65e5\u671f\u7b49\u9ad8\u7ea7\u6280\u5de7\u3002\u662f\u5b66\u4e60SQL\u7684\u597d\u4e66\u7c4d\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"\u4f7f\u7528SQL\u8bed\u53e5\u6765\u67e5\u627e\u4e00\u5217\u4e2d\u7684\u7b2cN\u5927\u503c\u4e3b\u8981\u6db5\u76d6\u4ee5\u4e0b\u51e0\u4e2a\u90e8\u5206\uff1a1. \u5982\u4f55\u4f7f\u7528ORDER BY\u8bed\u53e5\u548cLIMIT\u8bed\u53e5\u67e5 [&hellip;]","protected":false},"author":1,"featured_media":37707,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[37],"tags":[],"acf":[],"_links":{"self":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts\/37708"}],"collection":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/comments?post=37708"}],"version-history":[{"count":0,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts\/37708\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/media\/37707"}],"wp:attachment":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/media?parent=37708"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/categories?post=37708"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/tags?post=37708"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}