{"id":94600,"date":"2024-10-19T19:36:18","date_gmt":"2024-10-19T11:36:18","guid":{"rendered":"https:\/\/server.hk\/cnblog\/94600\/"},"modified":"2024-10-19T19:36:19","modified_gmt":"2024-10-19T11:36:19","slug":"oracle-%e5%87%bd%e6%95%b8%e7%94%a8%e6%b3%95%e4%b9%8bdecode%e8%a7%a3%e5%89%96","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/94600\/","title":{"rendered":"Oracle \u51fd\u6578\u7528\u6cd5\u4e4bdecode\u89e3\u5256"},"content":{"rendered":"<h1 id=\"oracle-%e5%87%bd%e6%95%b8%e7%94%a8%e6%b3%95%e4%b9%8bdecode%e8%a7%a3%e5%89%96-jZsBOZzRoJ\">Oracle \u51fd\u6578\u7528\u6cd5\u4e4bdecode\u89e3\u5256<\/h1>\n<p>\u5728 Oracle \u6578\u64da\u5eab\u4e2d\uff0c<code>DECODE<\/code> \u51fd\u6578\u662f\u4e00\u500b\u975e\u5e38\u6709\u7528\u7684\u5de5\u5177\uff0c\u80fd\u5920\u6839\u64da\u7279\u5b9a\u689d\u4ef6\u8fd4\u56de\u4e0d\u540c\u7684\u503c\u3002\u9019\u500b\u51fd\u6578\u7684\u8a9e\u6cd5\u7c21\u55ae\u660e\u77ad\uff0c\u4e26\u4e14\u5728\u6578\u64da\u67e5\u8a62\u548c\u5831\u544a\u4e2d\u7d93\u5e38\u88ab\u4f7f\u7528\u3002\u672c\u6587\u5c07\u6df1\u5165\u63a2\u8a0e <code>DECODE<\/code> \u51fd\u6578\u7684\u7528\u6cd5\uff0c\u4e26\u63d0\u4f9b\u4e00\u4e9b\u5be6\u969b\u7684\u7bc4\u4f8b\u4f86\u5e6b\u52a9\u8b80\u8005\u66f4\u597d\u5730\u7406\u89e3\u5176\u529f\u80fd\u3002<\/p>\n<h2 id=\"decode-%e5%87%bd%e6%95%b8%e7%9a%84%e5%9f%ba%e6%9c%ac%e8%aa%9e%e6%b3%95-jZsBOZzRoJ\">DECODE \u51fd\u6578\u7684\u57fa\u672c\u8a9e\u6cd5<\/h2>\n<p><code>DECODE<\/code> \u51fd\u6578\u7684\u57fa\u672c\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre><code>DECODE(expression, search, result, ..., default)<\/code><\/pre>\n<p>\u5728\u9019\u88e1\uff0c<code>expression<\/code> \u662f\u8981\u9032\u884c\u6bd4\u8f03\u7684\u503c\uff0c<code>search<\/code> \u662f\u8981\u5339\u914d\u7684\u503c\uff0c<code>result<\/code> \u662f\u7576 <code>expression<\/code> \u8207 <code>search<\/code> \u5339\u914d\u6642\u8fd4\u56de\u7684\u503c\u3002\u5982\u679c\u6c92\u6709\u5339\u914d\u7684\u503c\uff0c\u5247\u8fd4\u56de <code>default<\/code> \u503c\uff08\u5982\u679c\u63d0\u4f9b\u7684\u8a71\uff09\u3002<\/p>\n<h2 id=\"decode-%e5%87%bd%e6%95%b8%e7%9a%84%e4%bd%bf%e7%94%a8%e7%af%84%e4%be%8b-jZsBOZzRoJ\">DECODE \u51fd\u6578\u7684\u4f7f\u7528\u7bc4\u4f8b<\/h2>\n<p>\u4ee5\u4e0b\u662f\u4e00\u4e9b\u4f7f\u7528 <code>DECODE<\/code> \u51fd\u6578\u7684\u7bc4\u4f8b\uff0c\u5e6b\u52a9\u8b80\u8005\u7406\u89e3\u5176\u5be6\u969b\u61c9\u7528\u3002<\/p>\n<h3 id=\"%e7%af%84%e4%be%8b-1%ef%bc%9a%e7%b0%a1%e5%96%ae%e7%9a%84%e6%a2%9d%e4%bb%b6%e5%88%a4%e6%96%b7-jZsBOZzRoJ\">\u7bc4\u4f8b 1\uff1a\u7c21\u55ae\u7684\u689d\u4ef6\u5224\u65b7<\/h3>\n<p>\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u540d\u70ba <code>employees<\/code> \u7684\u8868\u683c\uff0c\u5176\u4e2d\u5305\u542b\u54e1\u5de5\u7684 <code>job_id<\/code> \u548c <code>salary<\/code>\u3002\u6211\u5011\u5e0c\u671b\u6839\u64da <code>job_id<\/code> \u8fd4\u56de\u4e0d\u540c\u7684\u85aa\u6c34\u7b49\u7d1a\uff1a<\/p>\n<pre><code>SELECT employee_id, job_id,\n       DECODE(job_id, \n              'IT_PROG', '\u9ad8',\n              'HR_REP', '\u4e2d',\n              'SA_REP', '\u4f4e',\n              '\u672a\u77e5') AS salary_grade\nFROM employees;<\/code><\/pre>\n<p>\u5728\u9019\u500b\u67e5\u8a62\u4e2d\uff0c\u6839\u64da <code>job_id<\/code> \u7684\u4e0d\u540c\uff0c<code>DECODE<\/code> \u51fd\u6578\u5c07\u8fd4\u56de\u76f8\u61c9\u7684\u85aa\u6c34\u7b49\u7d1a\u3002\u5982\u679c <code>job_id<\/code> \u4e0d\u5728\u6307\u5b9a\u7684\u9078\u9805\u4e2d\uff0c\u5247\u8fd4\u56de &#8216;\u672a\u77e5&#8217;\u3002<\/p>\n<h3 id=\"%e7%af%84%e4%be%8b-2%ef%bc%9a%e5%a4%9a%e9%87%8d%e6%a2%9d%e4%bb%b6%e5%88%a4%e6%96%b7-jZsBOZzRoJ\">\u7bc4\u4f8b 2\uff1a\u591a\u91cd\u689d\u4ef6\u5224\u65b7<\/h3>\n<p>\u6211\u5011\u4e5f\u53ef\u4ee5\u4f7f\u7528 <code>DECODE<\/code> \u51fd\u6578\u4f86\u8655\u7406\u591a\u91cd\u689d\u4ef6\u3002\u4f8b\u5982\uff0c\u5047\u8a2d\u6211\u5011\u60f3\u8981\u6839\u64da\u54e1\u5de5\u7684\u85aa\u6c34\u4f86\u5206\u985e\uff1a<\/p>\n<pre><code>SELECT employee_id, salary,\n       DECODE(SIGN(salary - 5000), \n              1, '\u9ad8',\n              0, '\u4e2d',\n              -1, '\u4f4e') AS salary_category\nFROM employees;<\/code><\/pre>\n<p>\u5728\u9019\u500b\u4f8b\u5b50\u4e2d\uff0c<code>SIGN<\/code> \u51fd\u6578\u7528\u4f86\u5224\u65b7\u85aa\u6c34\u662f\u5426\u9ad8\u65bc 5000\uff0c\u7136\u5f8c <code>DECODE<\/code> \u51fd\u6578\u6839\u64da\u7d50\u679c\u8fd4\u56de &#8216;\u9ad8&#8217;\u3001&#8217;\u4e2d&#8217; \u6216 &#8216;\u4f4e&#8217;\u3002<\/p>\n<h2 id=\"decode-%e5%87%bd%e6%95%b8%e7%9a%84%e5%84%aa%e7%bc%ba%e9%bb%9e-jZsBOZzRoJ\">DECODE \u51fd\u6578\u7684\u512a\u7f3a\u9ede<\/h2>\n<p>\u4f7f\u7528 <code>DECODE<\/code> \u51fd\u6578\u6709\u5176\u512a\u9ede\u548c\u7f3a\u9ede\uff1a<\/p>\n<ul>\n<li><strong>\u512a\u9ede\uff1a<\/strong>\u8a9e\u6cd5\u7c21\u55ae\uff0c\u6613\u65bc\u7406\u89e3\uff0c\u9069\u5408\u7528\u65bc\u7c21\u55ae\u7684\u689d\u4ef6\u5224\u65b7\u3002<\/li>\n<li><strong>\u7f3a\u9ede\uff1a<\/strong>\u7576\u689d\u4ef6\u8b8a\u5f97\u8907\u96dc\u6642\uff0c<code>DECODE<\/code> \u51fd\u6578\u7684\u53ef\u8b80\u6027\u6703\u4e0b\u964d\uff0c\u9019\u6642\u5019\u4f7f\u7528 <code>CASE<\/code> \u8a9e\u53e5\u53ef\u80fd\u6703\u66f4\u5408\u9069\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b5%90%e8%ab%96-jZsBOZzRoJ\">\u7d50\u8ad6<\/h2>\n<p>\u7e3d\u7d50\u4f86\u8aaa\uff0c<code>DECODE<\/code> \u51fd\u6578\u5728 Oracle \u6578\u64da\u5eab\u4e2d\u662f\u4e00\u500b\u5f37\u5927\u7684\u5de5\u5177\uff0c\u80fd\u5920\u6839\u64da\u4e0d\u540c\u7684\u689d\u4ef6\u8fd4\u56de\u76f8\u61c9\u7684\u503c\u3002\u96d6\u7136\u5728\u8655\u7406\u7c21\u55ae\u7684\u689d\u4ef6\u6642\u975e\u5e38\u65b9\u4fbf\uff0c\u4f46\u5728\u9762\u5c0d\u66f4\u8907\u96dc\u7684\u908f\u8f2f\u6642\uff0c\u8003\u616e\u4f7f\u7528 <code>CASE<\/code> \u8a9e\u53e5\u53ef\u80fd\u6703\u66f4\u70ba\u5408\u9069\u3002\u5e0c\u671b\u672c\u6587\u80fd\u5e6b\u52a9\u8b80\u8005\u66f4\u597d\u5730\u7406\u89e3 <code>DECODE<\/code> \u51fd\u6578\u7684\u7528\u6cd5\uff0c\u4e26\u5728\u5be6\u969b\u5de5\u4f5c\u4e2d\u9748\u6d3b\u904b\u7528\u3002<\/p>\n<p>\u5982\u9700\u4e86\u89e3\u66f4\u591a\u6709\u95dc <a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a> \u53ca\u5176\u4ed6\u4f3a\u670d\u5668\u89e3\u6c7a\u65b9\u6848\u7684\u4fe1\u606f\uff0c\u8acb\u8a2a\u554f\u6211\u5011\u7684\u7db2\u7ad9\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u6df1\u5165\u89e3\u6790Oracle\u51fd\u6578decode\u7684\u7528\u6cd5\uff0c\u5b78\u7fd2\u5982\u4f55\u5728\u67e5\u8a62\u4e2d\u9032\u884c\u689d\u4ef6\u5224\u65b7\u8207\u6578\u64da\u8f49\u63db\uff0c\u63d0\u5347SQL\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-94600","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/94600","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=94600"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/94600\/revisions"}],"predecessor-version":[{"id":94601,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/94600\/revisions\/94601"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=94600"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=94600"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=94600"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}