{"id":95352,"date":"2024-10-20T00:20:19","date_gmt":"2024-10-19T16:20:19","guid":{"rendered":"https:\/\/server.hk\/cnblog\/95352\/"},"modified":"2024-10-20T00:20:19","modified_gmt":"2024-10-19T16:20:19","slug":"oracle%e5%af%a6%e7%8f%betop-n%e7%9a%84%e6%ad%a3%e7%a2%ba%e6%93%8d%e4%bd%9c%e6%ad%a5%e9%a9%9f","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/95352\/","title":{"rendered":"Oracle\u5be6\u73fetop N\u7684\u6b63\u78ba\u64cd\u4f5c\u6b65\u9a5f"},"content":{"rendered":"<h1 id=\"oracle%e5%af%a6%e7%8f%betop-n%e7%9a%84%e6%ad%a3%e7%a2%ba%e6%93%8d%e4%bd%9c%e6%ad%a5%e9%a9%9f-CmjkkUtDAk\">Oracle\u5be6\u73feTop N\u7684\u6b63\u78ba\u64cd\u4f5c\u6b65\u9a5f<\/h1>\n<p>\u5728\u6578\u64da\u5eab\u7ba1\u7406\u4e2d\uff0c\u7372\u53d6Top N\u8a18\u9304\u662f\u4e00\u500b\u5e38\u898b\u7684\u9700\u6c42\u3002\u7121\u8ad6\u662f\u70ba\u4e86\u5831\u544a\u3001\u5206\u6790\u9084\u662f\u5176\u4ed6\u76ee\u7684\uff0cOracle\u6578\u64da\u5eab\u63d0\u4f9b\u4e86\u591a\u7a2e\u65b9\u6cd5\u4f86\u5be6\u73fe\u9019\u4e00\u529f\u80fd\u3002\u672c\u6587\u5c07\u4ecb\u7d39\u5728Oracle\u4e2d\u5be6\u73feTop N\u7684\u6b63\u78ba\u64cd\u4f5c\u6b65\u9a5f\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%a8rownum%e7%8d%b2%e5%8f%96top-n%e8%a8%98%e9%8c%84-CmjkkUtDAk\">1. \u4f7f\u7528ROWNUM\u7372\u53d6Top N\u8a18\u9304<\/h2>\n<p>\u5728Oracle\u4e2d\uff0c\u6700\u7c21\u55ae\u7684\u65b9\u6cd5\u4e4b\u4e00\u662f\u4f7f\u7528ROWNUM\u3002ROWNUM\u662f\u4e00\u500b\u865b\u64ec\u5217\uff0c\u8868\u793a\u67e5\u8a62\u7d50\u679c\u4e2d\u7684\u884c\u865f\u3002\u4ee5\u4e0b\u662f\u4f7f\u7528ROWNUM\u7372\u53d6Top N\u8a18\u9304\u7684\u57fa\u672c\u8a9e\u6cd5\uff1a<\/p>\n<pre><code>\nSELECT *\nFROM (\n    SELECT column1, column2\n    FROM your_table\n    ORDER BY column1 DESC\n)\nWHERE ROWNUM &lt;= N;\n<\/code><\/pre>\n<p>\u5728\u9019\u500b\u4f8b\u5b50\u4e2d\uff0c\u5c07\u201cyour_table\u201d\u66ff\u63db\u70ba\u4f60\u7684\u8868\u540d\uff0c\u4e26\u5c07\u201ccolumn1\u201d\u66ff\u63db\u70ba\u4f60\u5e0c\u671b\u6392\u5e8f\u7684\u5217\u3002N\u5247\u662f\u4f60\u60f3\u8981\u7372\u53d6\u7684\u8a18\u9304\u6578\u91cf\u3002<\/p>\n<h2 id=\"2-%e4%bd%bf%e7%94%a8%e5%88%86%e6%9e%90%e5%87%bd%e6%95%b8row_number%e7%8d%b2%e5%8f%96top-n%e8%a8%98%e9%8c%84-CmjkkUtDAk\">2. \u4f7f\u7528\u5206\u6790\u51fd\u6578ROW_NUMBER()\u7372\u53d6Top N\u8a18\u9304<\/h2>\n<p>\u53e6\u4e00\u7a2e\u66f4\u9748\u6d3b\u7684\u65b9\u6cd5\u662f\u4f7f\u7528\u5206\u6790\u51fd\u6578ROW_NUMBER()\u3002\u9019\u7a2e\u65b9\u6cd5\u5141\u8a31\u4f60\u5728\u5206\u7d44\u7684\u57fa\u790e\u4e0a\u7372\u53d6Top N\u8a18\u9304\u3002\u4ee5\u4e0b\u662f\u4f7f\u7528ROW_NUMBER()\u7684\u793a\u4f8b\uff1a<\/p>\n<pre><code>\nSELECT *\nFROM (\n    SELECT column1, column2, ROW_NUMBER() OVER (PARTITION BY column3 ORDER BY column1 DESC) AS rn\n    FROM your_table\n)\nWHERE rn &lt;= N;\n<\/code><\/pre>\n<p>\u5728\u9019\u88e1\uff0cPARTITION BY\u5b50\u53e5\u7528\u65bc\u6307\u5b9a\u5206\u7d44\u7684\u5217\uff0c\u800cORDER BY\u5b50\u53e5\u5247\u7528\u65bc\u78ba\u5b9a\u6392\u5e8f\u7684\u5217\u3002\u9019\u6a23\uff0c\u4f60\u53ef\u4ee5\u5728\u6bcf\u500b\u5206\u7d44\u4e2d\u7372\u53d6Top N\u8a18\u9304\u3002<\/p>\n<h2 id=\"3-%e4%bd%bf%e7%94%a8fetch-first-n-rows-only-CmjkkUtDAk\">3. \u4f7f\u7528FETCH FIRST N ROWS ONLY<\/h2>\n<p>\u5f9eOracle 12c\u958b\u59cb\uff0c\u9084\u53ef\u4ee5\u4f7f\u7528FETCH FIRST N ROWS ONLY\u8a9e\u6cd5\u4f86\u7372\u53d6Top N\u8a18\u9304\u3002\u9019\u7a2e\u65b9\u6cd5\u66f4\u52a0\u7c21\u6f54\uff0c\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre><code>\nSELECT column1, column2\nFROM your_table\nORDER BY column1 DESC\nFETCH FIRST N ROWS ONLY;\n<\/code><\/pre>\n<p>\u9019\u7a2e\u65b9\u6cd5\u4e0d\u50c5\u7c21\u55ae\uff0c\u800c\u4e14\u53ef\u8b80\u6027\u5f37\uff0c\u9069\u5408\u7528\u65bc\u7c21\u55ae\u7684\u67e5\u8a62\u3002<\/p>\n<h2 id=\"4-%e5%af%a6%e9%9a%9b%e6%87%89%e7%94%a8%e7%a4%ba%e4%be%8b-CmjkkUtDAk\">4. \u5be6\u969b\u61c9\u7528\u793a\u4f8b<\/h2>\n<p>\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u540d\u70ba\u201csales\u201d\u7684\u8868\uff0c\u5305\u542b\u201csalesperson_id\u201d\u3001\u201camount\u201d\u548c\u201cregion\u201d\u4e09\u500b\u5217\u3002\u6211\u5011\u5e0c\u671b\u7372\u53d6\u6bcf\u500b\u5730\u5340\u92b7\u552e\u984d\u6700\u9ad8\u7684\u524d3\u540d\u92b7\u552e\u4eba\u54e1\u3002\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u67e5\u8a62\uff1a<\/p>\n<pre><code>\nSELECT *\nFROM (\n    SELECT salesperson_id, amount, region, ROW_NUMBER() OVER (PARTITION BY region ORDER BY amount DESC) AS rn\n    FROM sales\n)\nWHERE rn &lt;= 3;\n<\/code><\/pre>\n<p>\u9019\u6a23\uff0c\u6211\u5011\u5c31\u80fd\u5920\u7372\u53d6\u6bcf\u500b\u5730\u5340\u92b7\u552e\u984d\u6700\u9ad8\u7684\u524d3\u540d\u92b7\u552e\u4eba\u54e1\u3002<\/p>\n<h2 id=\"5-%e6%b3%a8%e6%84%8f%e4%ba%8b%e9%a0%85-CmjkkUtDAk\">5. \u6ce8\u610f\u4e8b\u9805<\/h2>\n<ul>\n<li>\u5728\u4f7f\u7528ROWNUM\u6642\uff0c\u5fc5\u9808\u6ce8\u610f\u5176\u5728\u67e5\u8a62\u4e2d\u7684\u4f4d\u7f6e\uff0c\u56e0\u70ba\u5b83\u662f\u5728\u7d50\u679c\u96c6\u751f\u6210\u5f8c\u8a08\u7b97\u7684\u3002<\/li>\n<li>\u4f7f\u7528\u5206\u6790\u51fd\u6578\u6642\uff0c\u78ba\u4fdd\u7406\u89e3PARTITION BY\u548cORDER BY\u7684\u7528\u6cd5\uff0c\u4ee5\u4fbf\u6b63\u78ba\u7372\u53d6\u6240\u9700\u7684\u8a18\u9304\u3002<\/li>\n<li>FETCH FIRST N ROWS ONLY\u8a9e\u6cd5\u50c5\u9069\u7528\u65bcOracle 12c\u53ca\u4ee5\u4e0a\u7248\u672c\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b8%bd%e7%b5%90-CmjkkUtDAk\">\u7e3d\u7d50<\/h2>\n<p>\u5728Oracle\u4e2d\u5be6\u73feTop N\u8a18\u9304\u7684\u65b9\u6cd5\u6709\u591a\u7a2e\uff0c\u5305\u62ec\u4f7f\u7528ROWNUM\u3001ROW_NUMBER()\u548cFETCH FIRST N ROWS ONLY\u7b49\u3002\u6839\u64da\u5177\u9ad4\u9700\u6c42\u9078\u64c7\u5408\u9069\u7684\u65b9\u6cd5\uff0c\u53ef\u4ee5\u6709\u6548\u63d0\u9ad8\u67e5\u8a62\u6548\u7387\u548c\u53ef\u8b80\u6027\u3002\u5c0d\u65bc\u9700\u8981\u9ad8\u6548\u6578\u64da\u8655\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\u63d0\u5347\u6574\u9ad4\u6027\u80fd\uff0c\u7279\u5225\u662f\u5728\u9999\u6e2f\u5730\u5340\u7684\u6578\u64da\u8655\u7406\u9700\u6c42\u4e2d\uff0c\u9078\u64c7\u5408\u9069\u7684<a href=\"https:\/\/server.hk\">\u9999\u6e2f\u4f3a\u670d\u5668<\/a>\u5c07\u662f\u660e\u667a\u4e4b\u8209\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4e86\u89e3Oracle\u4e2d\u5be6\u73feTop N\u67e5\u8a62\u7684\u6b63\u78ba\u64cd\u4f5c\u6b65\u9a5f\uff0c\u63d0\u5347\u6578\u64da\u6aa2\u7d22\u6548\u7387\uff0c\u7c21\u5316\u6578\u64da\u5206\u6790\u904e\u7a0b\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-95352","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/95352","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=95352"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/95352\/revisions"}],"predecessor-version":[{"id":95353,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/95352\/revisions\/95353"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=95352"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=95352"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=95352"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}