{"id":96244,"date":"2024-10-20T07:48:17","date_gmt":"2024-10-19T23:48:17","guid":{"rendered":"https:\/\/server.hk\/cnblog\/96244\/"},"modified":"2024-10-20T07:48:17","modified_gmt":"2024-10-19T23:48:17","slug":"oracle%e4%b8%adrownum%e7%94%a8%e6%b3%95%e7%b8%bd%e7%b5%90","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/96244\/","title":{"rendered":"Oracle\u4e2drownum\u7528\u6cd5\u7e3d\u7d50"},"content":{"rendered":"<h1 id=\"oracle%e4%b8%adrownum%e7%94%a8%e6%b3%95%e7%b8%bd%e7%b5%90-fABVLeFBem\">Oracle\u4e2drownum\u7528\u6cd5\u7e3d\u7d50<\/h1>\n<p>\u5728Oracle\u6578\u64da\u5eab\u4e2d\uff0c<code>rownum<\/code>\u662f\u4e00\u500b\u975e\u5e38\u6709\u7528\u7684\u4f3a\u670d\u5668\u7aef\u507d\u5217\uff0c\u7528\u65bc\u9650\u5236\u67e5\u8a62\u7d50\u679c\u7684\u884c\u6578\u3002\u5b83\u5728\u6578\u64da\u6aa2\u7d22\u904e\u7a0b\u4e2d\u63d0\u4f9b\u4e86\u4e00\u7a2e\u7c21\u55ae\u7684\u65b9\u5f0f\u4f86\u63a7\u5236\u8fd4\u56de\u7684\u8a18\u9304\u6578\u91cf\u3002\u672c\u6587\u5c07\u6df1\u5165\u63a2\u8a0e<code>rownum<\/code>\u7684\u7528\u6cd5\u53ca\u5176\u5728\u5be6\u969b\u61c9\u7528\u4e2d\u7684\u4e00\u4e9b\u6ce8\u610f\u4e8b\u9805\u3002<\/p>\n<h2 id=\"%e4%bb%80%e9%ba%bc%e6%98%afrownum%ef%bc%9f-fABVLeFBem\">\u4ec0\u9ebc\u662frownum\uff1f<\/h2>\n<p><code>rownum<\/code>\u662fOracle\u6578\u64da\u5eab\u4e2d\u7684\u4e00\u500b\u507d\u5217\uff0c\u8868\u793a\u67e5\u8a62\u7d50\u679c\u96c6\u4e2d\u6bcf\u4e00\u884c\u7684\u5e8f\u865f\u3002\u7576\u67e5\u8a62\u57f7\u884c\u6642\uff0cOracle\u6703\u70ba\u6bcf\u4e00\u884c\u5206\u914d\u4e00\u500b\u552f\u4e00\u7684\u5e8f\u865f\uff0c\u5f9e1\u958b\u59cb\u905e\u589e\u3002\u9019\u4f7f\u5f97\u7528\u6236\u53ef\u4ee5\u8f15\u9b06\u5730\u9650\u5236\u67e5\u8a62\u7d50\u679c\u7684\u884c\u6578\u3002<\/p>\n<h2 id=\"%e5%9f%ba%e6%9c%ac%e7%94%a8%e6%b3%95-fABVLeFBem\">\u57fa\u672c\u7528\u6cd5<\/h2>\n<p>\u4f7f\u7528<code>rownum<\/code>\u7684\u57fa\u672c\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre><code>SELECT * FROM table_name WHERE ROWNUM &lt;= n;<\/code><\/pre>\n<p>\u5728\u9019\u88e1\uff0c<code>n<\/code>\u662f\u7528\u6236\u5e0c\u671b\u8fd4\u56de\u7684\u884c\u6578\u3002\u4f8b\u5982\uff0c\u5982\u679c\u6211\u5011\u60f3\u5f9e\u4e00\u500b\u540d\u70ba<code>employees<\/code>\u7684\u8868\u4e2d\u7372\u53d6\u524d10\u689d\u8a18\u9304\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u67e5\u8a62\uff1a<\/p>\n<pre><code>SELECT * FROM employees WHERE ROWNUM &lt;= 10;<\/code><\/pre>\n<h2 id=\"rownum%e7%9a%84%e7%89%b9%e6%80%a7-fABVLeFBem\">rownum\u7684\u7279\u6027<\/h2>\n<ul>\n<li><strong>\u884c\u865f\u5206\u914d\u9806\u5e8f\uff1a<\/strong>Oracle\u5728\u67e5\u8a62\u57f7\u884c\u6642\uff0c\u6703\u5728\u7d50\u679c\u96c6\u751f\u6210\u4e4b\u524d\u70ba\u6bcf\u4e00\u884c\u5206\u914d<code>rownum<\/code>\u3002\u56e0\u6b64\uff0c<code>rownum<\/code>\u7684\u503c\u662f\u57fa\u65bc\u67e5\u8a62\u7684\u57f7\u884c\u9806\u5e8f\uff0c\u800c\u4e0d\u662f\u6700\u7d42\u7684\u6392\u5e8f\u7d50\u679c\u3002<\/li>\n<li><strong>\u9650\u5236\u689d\u4ef6\u7684\u4f7f\u7528\uff1a<\/strong>\u5728\u4f7f\u7528<code>rownum<\/code>\u6642\uff0c\u5fc5\u9808\u6ce8\u610f\u5b83\u7684\u9650\u5236\u689d\u4ef6\u3002<code>rownum<\/code>\u7684\u503c\u5728\u67e5\u8a62\u904e\u7a0b\u4e2d\u662f\u52d5\u614b\u751f\u6210\u7684\uff0c\u56e0\u6b64\u5728\u4f7f\u7528<code>rownum<\/code>\u9032\u884c\u7be9\u9078\u6642\uff0c\u5fc5\u9808\u5c07\u5176\u653e\u5728<code>WHERE<\/code>\u5b50\u53e5\u4e2d\u3002<\/li>\n<\/ul>\n<h2 id=\"%e4%bd%bf%e7%94%a8rownum%e9%80%b2%e8%a1%8c%e6%8e%92%e5%ba%8f-fABVLeFBem\">\u4f7f\u7528rownum\u9032\u884c\u6392\u5e8f<\/h2>\n<p>\u5982\u679c\u9700\u8981\u5728\u6392\u5e8f\u5f8c\u9650\u5236\u7d50\u679c\u96c6\u7684\u884c\u6578\uff0c\u5247\u9700\u8981\u4f7f\u7528\u5b50\u67e5\u8a62\u3002\u56e0\u70ba<code>rownum<\/code>\u662f\u5728\u7d50\u679c\u96c6\u751f\u6210\u6642\u5206\u914d\u7684\uff0c\u6240\u4ee5\u5728\u6392\u5e8f\u5f8c\u518d\u4f7f\u7528<code>rownum<\/code>\u662f\u7121\u6cd5\u76f4\u63a5\u5be6\u73fe\u7684\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u793a\u4f8b\uff1a<\/p>\n<pre><code>SELECT * FROM (SELECT * FROM employees ORDER BY salary DESC) WHERE ROWNUM &lt;= 5;<\/code><\/pre>\n<p>\u5728\u9019\u500b\u67e5\u8a62\u4e2d\uff0c\u9996\u5148\u5c0d<code>employees<\/code>\u8868\u9032\u884c\u85aa\u8cc7\u964d\u5e8f\u6392\u5e8f\uff0c\u7136\u5f8c\u518d\u5f9e\u6392\u5e8f\u5f8c\u7684\u7d50\u679c\u4e2d\u9078\u64c7\u524d5\u689d\u8a18\u9304\u3002<\/p>\n<h2 id=\"rownum%e7%9a%84%e9%99%90%e5%88%b6-fABVLeFBem\">rownum\u7684\u9650\u5236<\/h2>\n<ul>\n<li><strong>\u7121\u6cd5\u4f7f\u7528\u65bcGROUP BY\uff1a<\/strong>\u5728\u4f7f\u7528<code>GROUP BY<\/code>\u8a9e\u53e5\u6642\uff0c<code>rownum<\/code>\u7121\u6cd5\u76f4\u63a5\u61c9\u7528\uff0c\u56e0\u70ba\u5b83\u662f\u5728\u805a\u5408\u8a08\u7b97\u5f8c\u751f\u6210\u7684\u3002<\/li>\n<li><strong>\u4e0d\u652f\u6301OFFSET\uff1a<\/strong>\u5728Oracle\u4e2d\uff0c<code>rownum<\/code>\u4e0d\u652f\u6301\u76f4\u63a5\u7684OFFSET\u64cd\u4f5c\uff0c\u9019\u610f\u5473\u8457\u7121\u6cd5\u76f4\u63a5\u8df3\u904e\u4e00\u5b9a\u6578\u91cf\u7684\u884c\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b5%90%e8%ab%96-fABVLeFBem\">\u7d50\u8ad6<\/h2>\n<p>\u7e3d\u7d50\u4f86\u8aaa\uff0c<code>rownum<\/code>\u662f\u4e00\u500b\u5f37\u5927\u7684\u5de5\u5177\uff0c\u53ef\u4ee5\u5e6b\u52a9\u7528\u6236\u5728Oracle\u6578\u64da\u5eab\u4e2d\u6709\u6548\u5730\u9650\u5236\u67e5\u8a62\u7d50\u679c\u7684\u884c\u6578\u3002\u96d6\u7136\u5b83\u6709\u4e00\u4e9b\u9650\u5236\uff0c\u4f46\u901a\u904e\u5408\u7406\u7684\u4f7f\u7528\u5b50\u67e5\u8a62\u548c\u6392\u5e8f\uff0c\u53ef\u4ee5\u514b\u670d\u9019\u4e9b\u6311\u6230\u3002\u5c0d\u65bc\u9700\u8981\u9ad8\u6548\u6578\u64da\u6aa2\u7d22\u7684\u61c9\u7528\u5834\u666f\uff0c\u7406\u89e3<code>rownum<\/code>\u7684\u7528\u6cd5\u5c07\u662f\u975e\u5e38\u91cd\u8981\u7684\u3002<\/p>\n<p>\u5982\u679c\u60a8\u6b63\u5728\u5c0b\u627e\u9ad8\u6548\u7684\u6578\u64da\u5eab\u89e3\u6c7a\u65b9\u6848\uff0c\u8003\u616e\u4f7f\u7528\u6211\u5011\u7684<a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a>\u670d\u52d9\uff0c\u70ba\u60a8\u7684\u61c9\u7528\u63d0\u4f9b\u7a69\u5b9a\u7684\u652f\u6301\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u7e3d\u7d50Oracle\u4e2drownum\u7684\u7528\u6cd5\uff0c\u63a2\u8a0e\u5176\u5728\u67e5\u8a62\u7d50\u679c\u904e\u6ffe\u3001\u9650\u5236\u884c\u6578\u53ca\u6027\u80fd\u512a\u5316\u4e2d\u7684\u61c9\u7528\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-96244","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/96244","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=96244"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/96244\/revisions"}],"predecessor-version":[{"id":96245,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/96244\/revisions\/96245"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=96244"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=96244"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=96244"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}