{"id":5754,"date":"2024-11-14T08:48:07","date_gmt":"2024-11-14T00:48:07","guid":{"rendered":"https:\/\/fwq.ai\/blog\/5754\/"},"modified":"2024-11-14T08:48:07","modified_gmt":"2024-11-14T00:48:07","slug":"oracle-decode%e6%80%8e%e4%b9%88%e6%8e%92%e5%ba%8f%e7%9a%84-2","status":"publish","type":"post","link":"https:\/\/fwq.ai\/blog\/5754\/","title":{"rendered":"oracle decode\u600e\u4e48\u6392\u5e8f\u7684"},"content":{"rendered":"<blockquote><p>\n  oracle decode \u51fd\u6570\u7528\u4e8e\u57fa\u4e8e\u6761\u4ef6\u5c06\u8868\u8fbe\u5f0f\u8f6c\u6362\u4e3a\u6307\u5b9a\u503c\uff0c\u5728\u6392\u5e8f decode \u7ed3\u679c\u65f6\uff0coracle \u9075\u5faa\u4ee5\u4e0b\u89c4\u5219\uff1acase when \u8bed\u53e5\u6392\u5e8f\u6839\u636e when \u6761\u4ef6\u7684\u987a\u5e8f\u3002\u5176\u4ed6\u8868\u8fbe\u5f0f\u6392\u5e8f\u6839\u636e\u8868\u8fbe\u5f0f\u672c\u8eab\u3002null \u503c\u88ab\u89c6\u4e3a\u6700\u5c0f\u503c\u3002\u7f3a\u5931\u503c\u88ab\u5ffd\u7565\u3002\n<\/p><\/blockquote>\n<p><img decoding=\"async\" src=\"https:\/\/img.php.cn\/upload\/article\/202405\/30\/2024053022095711577.jpg\" class=\"aligncenter\" title=\"oracle decode\u600e\u4e48\u6392\u5e8f\u7684\u63d2\u56fe\" alt=\"oracle decode\u600e\u4e48\u6392\u5e8f\u7684\u63d2\u56fe\" \/><\/p>\n<p><strong>Oracle DECODE \u6392\u5e8f\u89c4\u5219<\/strong><\/p>\n<p>Oracle DECODE \u51fd\u6570\u7528\u4e8e\u57fa\u4e8e\u6761\u4ef6\u5c06\u8868\u8fbe\u5f0f\u8f6c\u6362\u4e3a\u6307\u5b9a\u503c\uff0c\u5728\u5bf9 DECODE \u51fd\u6570\u7684\u7ed3\u679c\u8fdb\u884c\u6392\u5e8f\u65f6\uff0cOracle \u9075\u5faa\u4ee5\u4e0b\u89c4\u5219\uff1a<\/p>\n<p><strong>1. CASE WHEN \u8bed\u53e5<\/strong><\/p>\n<p>\u5982\u679c\u60a8\u4f7f\u7528 CASE WHEN \u8bed\u53e5\u4f5c\u4e3a DECODE \u51fd\u6570\u7684\u7b2c\u4e00\u4e2a\u53c2\u6570\uff0c\u5219\u6392\u5e8f\u6839\u636e WHEN \u6761\u4ef6\u7684\u987a\u5e8f\u8fdb\u884c\u3002\u4f8b\u5982\uff1a<\/p>\n<pre>SELECT name, DECODE(gender, 'M', 'Male', 'F', 'Female') AS gender_label\nFROM employees\nORDER BY gender_label;<\/pre>\n<p> \u767b\u5f55\u540e\u590d\u5236 <\/p>\n<p>\u8fd9\u5c06\u6309\u6027\u522b\u6807\u7b7e\u5bf9\u5458\u5de5\u59d3\u540d\u8fdb\u884c\u6392\u5e8f\uff0c\u9996\u5148\u662f\u7537\u6027\uff0c\u7136\u540e\u662f\u5973\u6027\u3002<\/p>\n<p><strong>2. \u5176\u4ed6\u8868\u8fbe\u5f0f<\/strong><\/p>\n<p>\u5982\u679c DECODE \u51fd\u6570\u7684\u7b2c\u4e00\u4e2a\u53c2\u6570\u4e0d\u662f CASE WHEN \u8bed\u53e5\uff0c\u5219\u6392\u5e8f\u6839\u636e\u8868\u8fbe\u5f0f\u672c\u8eab\u8fdb\u884c\u3002\u4f8b\u5982\uff1a<\/p>\n<pre>SELECT name, DECODE(department, 10, 'Sales', 20, 'Marketing') AS department_label\nFROM employees\nORDER BY department_label;<\/pre>\n<p> \u767b\u5f55\u540e\u590d\u5236 <\/p>\n<p>\u8fd9\u5c06\u6309\u90e8\u95e8\u6807\u7b7e\u5bf9\u5458\u5de5\u59d3\u540d\u8fdb\u884c\u6392\u5e8f\uff0c\u9996\u5148\u662f\u9500\u552e\uff0c\u7136\u540e\u662f\u8425\u9500\u3002<\/p>\n<p><strong>3. NULL \u503c<\/strong><\/p>\n<p>NULL \u503c\u5728\u6392\u5e8f\u4e2d\u88ab\u89c6\u4e3a\u6700\u5c0f\u7684\u503c\uff0c\u56e0\u6b64\u5c06\u51fa\u73b0\u5728\u6392\u5e8f\u7ed3\u679c\u7684\u9876\u90e8\u3002<\/p>\n<p><strong>4. \u7f3a\u5931\u503c<\/strong><\/p>\n<p>\u5982\u679c DECODE \u51fd\u6570\u4e2d\u4f7f\u7528\u4e86\u7f3a\u5931\u503c\uff0c\u5219\u8fd9\u4e9b\u503c\u5c06\u88ab\u5ffd\u7565\uff0c\u5e76\u4e14\u4e0d\u4f1a\u5f71\u54cd\u6392\u5e8f\u7ed3\u679c\u3002<\/p>\n<p><strong>\u793a\u4f8b<\/strong><\/p>\n<p>\u4ee5\u4e0b\u662f\u4f7f\u7528\u4e0d\u540c\u6392\u5e8f\u89c4\u5219\u7684 DECODE \u51fd\u6570\u793a\u4f8b\uff1a<\/p>\n<p><strong>\u6309 CASE WHEN \u8bed\u53e5\u6392\u5e8f\uff1a<\/strong><\/p>\n<pre>SELECT *\nFROM employees\nORDER BY DECODE(gender, 'M', 1, 'F', 2);<\/pre>\n<p> \u767b\u5f55\u540e\u590d\u5236 <\/p>\n<p>\u8fd9\u5c06\u6309\u6027\u522b\u5bf9\u5458\u5de5\u8fdb\u884c\u6392\u5e8f\uff0c\u9996\u5148\u662f\u7537\u6027\uff0c\u7136\u540e\u662f\u5973\u6027\u3002<\/p>\n<p><strong>\u6309\u8868\u8fbe\u5f0f\u6392\u5e8f\uff1a<\/strong><\/p>\n<pre>SELECT *\nFROM employees\nORDER BY DECODE(salary, 10000, 1, 20000, 2, 30000, 3);<\/pre>\n<p> \u767b\u5f55\u540e\u590d\u5236 <\/p>\n<p>\u8fd9\u5c06\u6309\u5de5\u8d44\u5bf9\u5458\u5de5\u8fdb\u884c\u6392\u5e8f\uff0c\u9996\u5148\u662f\u6700\u4f4e\u5de5\u8d44\uff0c\u7136\u540e\u662f\u4e2d\u7b49\u5de5\u8d44\uff0c\u6700\u540e\u662f\u6700\u9ad8\u5de5\u8d44\u3002<\/p>\n<p>\u9700\u8981\u6ce8\u610f\u7684\u662f\uff0cOracle DECODE \u51fd\u6570\u4e0d\u76f4\u63a5\u63d0\u4f9b\u6392\u5e8f\u529f\u80fd\u3002\u76f8\u53cd\uff0c\u6392\u5e8f\u64cd\u4f5c\u662f\u7531 ORDER BY \u5b50\u53e5\u5355\u72ec\u5b8c\u6210\u7684\u3002<\/p>\n<p>\u4ee5\u4e0a\u5c31\u662f decode\u600e\u4e48\u6392\u5e8f\u7684\u7684\u8be6\u7ec6\u5185\u5bb9\uff0c\u66f4\u591a\u8bf7\u5173\u6ce8\u7c73\u4e91\u7f51\u5176\u5b83\u76f8\u5173\u6587\u7ae0\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"<p>oracle decode \u51fd\u6570\u7528\u4e8e\u57fa\u4e8e\u6761\u4ef6\u5c06\u8868\u8fbe\u5f0f\u8f6c\u6362\u4e3a\u6307\u5b9a\u503c\uff0c\u5728\u6392\u5e8f decode \u7ed3\u679c\u65f6\uff0coracle \u9075\u5faa\u4ee5\u4e0b\u89c4\u5219\uff1acase when \u8bed\u53e5\u6392\u5e8f\u6839\u636e when \u6761\u4ef6\u7684\u987a\u5e8f\u3002\u5176\u4ed6\u8868\u8fbe\u5f0f\u6392\u5e8f\u6839\u636e\u8868\u8fbe\u5f0f\u672c\u8eab\u3002null \u503c\u88ab\u89c6\u4e3a\u6700\u5c0f\u503c\u3002\u7f3a\u5931\u503c\u88ab\u5ffd\u7565\u3002 Oracle DECODE \u6392\u5e8f\u89c4\u5219 Oracle DECODE \u51fd\u6570\u7528\u4e8e\u57fa\u4e8e\u6761\u4ef6\u5c06\u8868\u8fbe\u5f0f\u8f6c\u6362\u4e3a\u6307\u5b9a\u503c\uff0c\u5728\u5bf9 DECODE \u51fd\u6570\u7684\u7ed3\u679c\u8fdb\u884c\u6392\u5e8f\u65f6\uff0cOracle \u9075\u5faa\u4ee5\u4e0b\u89c4\u5219\uff1a 1. CASE WHEN \u8bed\u53e5 \u5982\u679c\u60a8\u4f7f\u7528 CASE WHEN \u8bed\u53e5\u4f5c\u4e3a DECODE \u51fd\u6570\u7684\u7b2c\u4e00\u4e2a\u53c2\u6570\uff0c\u5219\u6392\u5e8f\u6839\u636e WHEN \u6761\u4ef6\u7684\u987a\u5e8f\u8fdb\u884c\u3002\u4f8b\u5982\uff1a SELECT name, DECODE(gender, &#8216;M&#8217;, &#8216;Male&#8217;, &#8216;F&#8217;, &#8216;Female&#8217;) AS gender_label FROM employees ORDER BY gender_label; \u767b\u5f55\u540e\u590d\u5236 \u8fd9\u5c06\u6309\u6027\u522b\u6807\u7b7e\u5bf9\u5458\u5de5\u59d3\u540d\u8fdb\u884c\u6392\u5e8f\uff0c\u9996\u5148\u662f\u7537\u6027\uff0c\u7136\u540e\u662f\u5973\u6027\u3002 2. \u5176\u4ed6\u8868\u8fbe\u5f0f \u5982\u679c DECODE \u51fd\u6570\u7684\u7b2c\u4e00\u4e2a\u53c2\u6570\u4e0d\u662f CASE WHEN [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[16],"tags":[],"class_list":["post-5754","post","type-post","status-publish","format-standard","hentry","category-16"],"_links":{"self":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/5754","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/comments?post=5754"}],"version-history":[{"count":0,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/5754\/revisions"}],"wp:attachment":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/media?parent=5754"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/categories?post=5754"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/tags?post=5754"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}