{"id":199892,"date":"2025-05-06T11:23:38","date_gmt":"2025-05-06T03:23:38","guid":{"rendered":"https:\/\/server.hk\/cnblog\/199892\/"},"modified":"2025-05-06T11:23:38","modified_gmt":"2025-05-06T03:23:38","slug":"%e5%88%86%e4%ba%aboracle-decode%e5%87%bd%e6%95%b0%e7%9a%84%e8%bf%9b%e9%98%b6%e5%ba%94%e7%94%a8%e5%92%8c%e6%8a%80%e5%b7%a7","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/199892\/","title":{"rendered":"\u5206\u4eabOracle DECODE\u51fd\u6570\u7684\u8fdb\u9636\u5e94\u7528\u548c\u6280\u5de7"},"content":{"rendered":"<p><b><\/b> <\/p>\n<h1>\u5206\u4eabOracle DECODE\u51fd\u6570\u7684\u8fdb\u9636\u5e94\u7528\u548c\u6280\u5de7<\/h1>\n<p>\u672c\u7bc7\u6587\u7ae0\u4e3b\u8981\u662f\u7ed3\u5408\u6211\u4e4b\u524d\u9762\u8bd5\u7684\u5404\u79cd\u7ecf\u5386\u548c\u5b9e\u6218\u5f00\u53d1\u4e2d\u9047\u5230\u7684\u95ee\u9898\u89e3\u51b3\u7ecf\u9a8c\u6574\u7406\u7684\uff0c\u5e0c\u671b\u8fd9\u7bc7\u300a\u5206\u4eabOracle DECODE\u51fd\u6570\u7684\u8fdb\u9636\u5e94\u7528\u548c\u6280\u5de7\u300b\u5bf9\u4f60\u6709\u5f88\u5927\u5e2e\u52a9\uff01\u6b22\u8fce\u6536\u85cf\uff0c\u5206\u4eab\u7ed9\u66f4\u591a\u7684\u9700\u8981\u7684\u670b\u53cb\u5b66\u4e60~<\/p>\n<p>Oracle\u6570\u636e\u5e93\u4e2d\u7684DECODE\u51fd\u6570\u662f\u4e00\u4e2a\u975e\u5e38\u5e38\u7528\u7684\u51fd\u6570\uff0c\u5b83\u53ef\u4ee5\u6839\u636e\u4e00\u4e2a\u8868\u8fbe\u5f0f\u7684\u7ed3\u679c\u503c\u5728\u4e00\u7ec4\u503c\u4e2d\u8fdb\u884c\u9009\u62e9\u3002DECODE\u51fd\u6570\u7684\u8bed\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre>DECODE(expression, search_value1, result1, search_value2, result2, ..., default_result)<\/pre>\n<p>\u5176\u4e2d\uff0cexpression\u662f\u8981\u8fdb\u884c\u6bd4\u8f83\u7684\u8868\u8fbe\u5f0f\uff0csearch_value1\u662f\u8981\u6bd4\u8f83\u7684\u503c\uff0cresult1\u662f\u5982\u679cexpression\u7b49\u4e8esearch_value1\u65f6\u8fd4\u56de\u7684\u7ed3\u679c\uff0c\u4f9d\u6b64\u7c7b\u63a8\u3002<\/p>\n<p>\u4e0b\u9762\u5c06\u4f1a\u4ecb\u7ecd\u4e00\u4e9bDECODE\u51fd\u6570\u7684\u9ad8\u7ea7\u7528\u6cd5\u53ca\u6280\u5de7\uff0c\u5e76\u63d0\u4f9b\u5177\u4f53\u7684\u4ee3\u7801\u793a\u4f8b\uff1a<\/p>\n<ol>\n<li>\u4f7f\u7528DECODE\u51fd\u6570\u5b9e\u73b0\u591a\u6761\u4ef6\u5224\u65ad\uff1a<\/li>\n<\/ol>\n<p>DECODE\u51fd\u6570\u53ef\u4ee5\u5b9e\u73b0\u591a\u6761\u4ef6\u5224\u65ad\uff0c\u5c06\u591a\u4e2a\u6761\u4ef6\u7ec4\u5408\u5728\u4e00\u8d77\u5224\u65ad\u3002\u4f8b\u5982\uff0c\u5224\u65ad\u5458\u5de5\u7684\u7b49\u7ea7\uff0c\u5982\u679c\u7b49\u7ea7\u4e3a1\u5219\u8fd4\u56de\u201c\u521d\u7ea7\u201d\uff0c\u7b49\u7ea7\u4e3a2\u5219\u8fd4\u56de\u201c\u4e2d\u7ea7\u201d\uff0c\u7b49\u7ea7\u4e3a3\u5219\u8fd4\u56de\u201c\u9ad8\u7ea7\u201d\uff0c\u5176\u4ed6\u60c5\u51b5\u8fd4\u56de\u201c\u672a\u77e5\u7ea7\u522b\u201d\u3002<\/p>\n<pre>SELECT name, DECODE(level,\n                        1, '\u521d\u7ea7',\n                        2, '\u4e2d\u7ea7',\n                        3, '\u9ad8\u7ea7',\n                        '\u672a\u77e5\u7ea7\u522b') AS level_name\nFROM employees;<\/pre>\n<ol>\n<li>\u4f7f\u7528DECODE\u51fd\u6570\u5bf9NULL\u503c\u8fdb\u884c\u5904\u7406\uff1a<\/li>\n<\/ol>\n<p>DECODE\u51fd\u6570\u53ef\u4ee5\u9488\u5bf9NULL\u503c\u8fdb\u884c\u5904\u7406\uff0c\u53ef\u4ee5\u5c06NULL\u503c\u8f6c\u6362\u4e3a\u5176\u4ed6\u503c\u3002\u4f8b\u5982\uff0c\u5c06NULL\u503c\u8f6c\u6362\u4e3a0\u3002<\/p>\n<pre>SELECT name, DECODE(salary,\n                        NULL, 0,\n                        salary) AS new_salary\nFROM employees;<\/pre>\n<ol>\n<li>\u4f7f\u7528DECODE\u51fd\u6570\u8fdb\u884c\u903b\u8f91\u8ba1\u7b97\uff1a<\/li>\n<\/ol>\n<p>DECODE\u51fd\u6570\u53ef\u4ee5\u8fdb\u884c\u903b\u8f91\u8ba1\u7b97\uff0c\u5b9e\u73b0\u7c7b\u4f3c\u4e8eIF-ELSE\u8bed\u53e5\u7684\u529f\u80fd\u3002\u4f8b\u5982\uff0c\u5982\u679c\u67d0\u4e2a\u5b57\u6bb5\u5c0f\u4e8e10\uff0c\u8fd4\u56de\u201c\u5c0f\u201d\uff0c\u5426\u5219\u8fd4\u56de\u201c\u5927\u201d\u3002<\/p>\n<pre>SELECT name, DECODE(quantity &lt; 10,\n                        1, '\u5c0f',\n                        '\u5927') AS size\nFROM products;<\/pre>\n<ol>\n<li>\u4f7f\u7528DECODE\u51fd\u6570\u8fdb\u884c\u6570\u636e\u8f6c\u6362\uff1a<\/li>\n<\/ol>\n<p>DECODE\u51fd\u6570\u8fd8\u53ef\u4ee5\u7528\u4e8e\u6570\u636e\u8f6c\u6362\uff0c\u5c06\u6570\u636e\u4ece\u4e00\u79cd\u5f62\u5f0f\u8f6c\u6362\u4e3a\u53e6\u4e00\u79cd\u5f62\u5f0f\u3002\u4f8b\u5982\uff0c\u5c06\u6027\u522b\u7f16\u7801\u8f6c\u6362\u4e3a\u6c49\u5b57\u5f62\u5f0f\u3002<\/p>\n<pre>SELECT name, DECODE(gender,\n                        'M', '\u7537',\n                        'F', '\u5973') AS gender_name\nFROM employees;<\/pre>\n<ol>\n<li>\u4f7f\u7528DECODE\u51fd\u6570\u8fdb\u884c\u8303\u56f4\u5224\u65ad\uff1a<\/li>\n<\/ol>\n<p>DECODE\u51fd\u6570\u53ef\u4ee5\u8fdb\u884c\u8303\u56f4\u5224\u65ad\uff0c\u5224\u65ad\u8868\u8fbe\u5f0f\u7684\u503c\u5728\u67d0\u4e2a\u8303\u56f4\u5185\u65f6\u8fd4\u56de\u4e0d\u540c\u7684\u7ed3\u679c\u3002\u4f8b\u5982\uff0c\u6839\u636e\u6210\u7ee9\u5224\u65ad\u5b66\u751f\u7684\u7ea7\u522b\u3002<\/p>\n<pre>SELECT name, DECODE(score,\n                        90, '\u4f18\u79c0',\n                        80, '\u826f\u597d',\n                        70, '\u53ca\u683c',\n                        '\u4e0d\u53ca\u683c') AS level\nFROM students;<\/pre>\n<p>\u901a\u8fc7\u4ee5\u4e0a\u793a\u4f8b\uff0c\u6211\u4eec\u53ef\u4ee5\u770b\u5230DECODE\u51fd\u6570\u5728Oracle\u6570\u636e\u5e93\u4e2d\u7684\u5f3a\u5927\u529f\u80fd\u548c\u7075\u6d3b\u6027\u3002\u5728\u5b9e\u9645\u5de5\u4f5c\u4e2d\uff0c\u5408\u7406\u5730\u8fd0\u7528DECODE\u51fd\u6570\u53ef\u4ee5\u7b80\u5316SQL\u8bed\u53e5\u7684\u7f16\u5199\uff0c\u63d0\u9ad8\u67e5\u8be2\u6548\u7387\uff0c\u540c\u65f6\u4e5f\u4f7f\u4ee3\u7801\u66f4\u52a0\u6e05\u6670\u6613\u61c2\u3002\u5e0c\u671b\u4ee5\u4e0a\u5185\u5bb9\u80fd\u5e2e\u52a9\u5404\u4f4d\u8bfb\u8005\u66f4\u597d\u5730\u4e86\u89e3\u548c\u5e94\u7528DECODE\u51fd\u6570\u3002<\/p>\n<p>\u4ee5\u4e0a\u5c31\u662f\u672c\u6587\u7684\u5168\u90e8\u5185\u5bb9\u4e86\uff0c\u662f\u5426\u6709\u987a\u5229\u5e2e\u52a9\u4f60\u89e3\u51b3\u95ee\u9898\uff1f\u82e5\u662f\u80fd\u7ed9\u4f60\u5e26\u6765\u5b66\u4e60\u4e0a\u7684\u5e2e\u52a9\uff0c\u8bf7\u5927\u5bb6\u591a\u591a\u652f\u6301\u4e3b\u673a\u5b9d\u8d1d\uff01\u66f4\u591a\u5173\u4e8e\u6570\u636e\u5e93\u7684\u76f8\u5173\u77e5\u8bc6\uff0c\u4e5f\u53ef\u5173\u6ce8\u4e3b\u673a\u5b9d\u8d1d\u516c\u4f17\u53f7\u3002<\/p>\n<dl>\n<dt>\n <\/dt>\n<\/dl>\n","protected":false},"excerpt":{"rendered":"<p>\u5206\u4eabOracle DECODE\u51fd&#46;&#46;&#46;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-199892","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/199892","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"}],"author":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=199892"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/199892\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=199892"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=199892"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=199892"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}