{"id":199835,"date":"2025-05-06T09:53:52","date_gmt":"2025-05-06T01:53:52","guid":{"rendered":"https:\/\/server.hk\/cnblog\/199835\/"},"modified":"2025-05-06T09:53:52","modified_gmt":"2025-05-06T01:53:52","slug":"%e8%a7%a3%e6%9e%90oracle-decode%e5%87%bd%e6%95%b0%e7%9a%84%e7%a4%ba%e4%be%8b%e5%92%8c%e4%bd%bf%e7%94%a8%e6%83%85%e5%86%b5","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/199835\/","title":{"rendered":"\u89e3\u6790Oracle DECODE\u51fd\u6570\u7684\u793a\u4f8b\u548c\u4f7f\u7528\u60c5\u51b5"},"content":{"rendered":"

<\/b> <\/p>\n

\u89e3\u6790Oracle DECODE\u51fd\u6570\u7684\u793a\u4f8b\u548c\u4f7f\u7528\u60c5\u51b5<\/h1>\n

\u6570\u636e\u5e93\u5c0f\u767d\u4e00\u679a\uff0c\u6b63\u5728\u4e0d\u65ad\u5b66\u4e60\u79ef\u7d2f\u77e5\u8bc6\uff0c\u73b0\u5c06\u5b66\u4e60\u5230\u7684\u77e5\u8bc6\u8bb0\u5f55\u4e00\u4e0b\uff0c\u4e5f\u662f\u5c06\u6211\u7684\u6240\u5f97\u5206\u4eab\u7ed9\u5927\u5bb6\uff01\u800c\u4eca\u5929\u8fd9\u7bc7\u6587\u7ae0\u300a\u89e3\u6790Oracle DECODE\u51fd\u6570\u7684\u793a\u4f8b\u548c\u4f7f\u7528\u60c5\u51b5\u300b\u5e26\u5927\u5bb6\u6765\u4e86\u89e3\u4e00\u4e0b##content_title##\uff0c\u5e0c\u671b\u5bf9\u5927\u5bb6\u7684\u77e5\u8bc6\u79ef\u7d2f\u6709\u6240\u5e2e\u52a9\uff0c\u4ece\u800c\u5f25\u8865\u81ea\u5df1\u7684\u4e0d\u8db3\uff0c\u52a9\u529b\u5b9e\u6218\u5f00\u53d1\uff01<\/p>\n

<\/p>\n

Oracle\u6570\u636e\u5e93\u662f\u4e00\u79cd\u6d41\u884c\u7684\u5173\u7cfb\u578b\u6570\u636e\u5e93\u7ba1\u7406\u7cfb\u7edf\uff0c\u5b83\u63d0\u4f9b\u4e86\u4e30\u5bcc\u7684\u51fd\u6570\u548c\u5de5\u5177\u6765\u5904\u7406\u590d\u6742\u7684\u6570\u636e\u64cd\u4f5c\u3002\u5176\u4e2d\uff0cDECODE\u51fd\u6570\u662f\u4e00\u4e2a\u975e\u5e38\u5e38\u7528\u7684\u51fd\u6570\u4e4b\u4e00\uff0c\u53ef\u4ee5\u6839\u636e\u6307\u5b9a\u7684\u6761\u4ef6\u5bf9\u6570\u636e\u8fdb\u884c\u8f6c\u6362\u548c\u5904\u7406\u3002\u672c\u6587\u5c06\u8be6\u7ec6\u4ecb\u7ecdOracle\u7684DECODE\u51fd\u6570\uff0c\u5305\u62ec\u8bed\u6cd5\u7ed3\u6784\u3001\u529f\u80fd\u7279\u70b9\u4ee5\u53ca\u5b9e\u9645\u5e94\u7528\u573a\u666f\uff0c\u5e76\u63d0\u4f9b\u5177\u4f53\u7684\u4ee3\u7801\u793a\u4f8b\u3002<\/p>\n

1. DECODE\u51fd\u6570\u7684\u8bed\u6cd5\u7ed3\u6784<\/h3>\n

DECODE\u51fd\u6570\u7684\u8bed\u6cd5\u7ed3\u6784\u5982\u4e0b\uff1a<\/p>\n

DECODE(\u8868\u8fbe\u5f0f,\u641c\u7d221,\u7ed3\u679c1,\u641c\u7d222,\u7ed3\u679c2,...,\u9ed8\u8ba4\u7ed3\u679c)<\/pre>\n
\u5176\u4e2d\uff0c\u8868\u8fbe\u5f0f\u662f\u9700\u8981\u8fdb\u884c\u6bd4\u8f83\u7684\u503c\uff0c\u641c\u7d221\u3001\u641c\u7d222\u7b49\u4e3a\u5177\u4f53\u7684\u641c\u7d22\u6761\u4ef6\uff0c\u7ed3\u679c1\u3001\u7ed3\u679c2\u7b49\u4e3a\u6ee1\u8db3\u5bf9\u5e94\u641c\u7d22\u6761\u4ef6\u65f6\u7684\u8fd4\u56de\u7ed3\u679c\uff0c\u6700\u540e\u4e00\u4e2a\u53c2\u6570\u4e3a\u9ed8\u8ba4\u7684\u8fd4\u56de\u7ed3\u679c\u3002<\/p>\n
2. DECODE\u51fd\u6570\u7684\u529f\u80fd\u7279\u70b9<\/h3>\n
    \n
  • DECODE\u51fd\u6570\u6839\u636e\u4e0d\u540c\u7684\u6761\u4ef6\u503c\u8fdb\u884c\u6bd4\u8f83\uff0c\u5e76\u8fd4\u56de\u5bf9\u5e94\u7684\u7ed3\u679c\u503c\u3002<\/li>\n
  • \u53ef\u4ee5\u8fdb\u884c\u591a\u6761\u4ef6\u7684\u5224\u65ad\uff0c\u6839\u636e\u4e0d\u540c\u7684\u6761\u4ef6\u8fd4\u56de\u4e0d\u540c\u7684\u7ed3\u679c\u3002<\/li>\n
  • DECODE\u51fd\u6570\u53ef\u4ee5\u5904\u7406NULL\u503c\uff0c\u63d0\u4f9b\u4e86\u5bf9\u7a7a\u503c\u7684\u517c\u5bb9\u6027\u5904\u7406\u3002<\/li>\n<\/ul>\n
    3. DECODE\u51fd\u6570\u7684\u4f7f\u7528\u793a\u4f8b<\/h3>\n
    \u63a5\u4e0b\u6765\uff0c\u6211\u4eec\u5c06\u901a\u8fc7\u51e0\u4e2a\u5177\u4f53\u7684\u4ee3\u7801\u793a\u4f8b\u6765\u6f14\u793aDECODE\u51fd\u6570\u7684\u7528\u6cd5\u3002<\/p>\n
    \u793a\u4f8b1\uff1a\u6839\u636e\u4e0d\u540c\u5206\u6570\u8303\u56f4\u5224\u65ad\u7b49\u7ea7<\/strong><\/p>\n
    \u5047\u8bbe\u6709\u4e00\u4e2a\u6210\u7ee9\u8868\uff0c\u6bcf\u4e2a\u5b66\u751f\u7684\u5206\u6570\u5b58\u5728\u5b57\u6bb5score\uff0c\u6211\u4eec\u8981\u6839\u636e\u4e0d\u540c\u7684\u5206\u6570\u8303\u56f4\u5224\u65ad\u5b66\u751f\u7684\u7b49\u7ea7\uff0c\u53ef\u4ee5\u4f7f\u7528\u5982\u4e0b\u4ee3\u7801\uff1a<\/p>\n
    SELECT student_name, DECODE(score,\n    90, 'A',\n    80, 'B',\n    70, 'C',\n    'D'\n) AS grade\nFROM student_table;<\/pre>\n
    \u5728\u8fd9\u4e2a\u793a\u4f8b\u4e2d\uff0c\u6839\u636e\u5b66\u751f\u7684\u5206\u6570\u4e0d\u540c\uff0c\u8fd4\u56de\u5bf9\u5e94\u7684\u7b49\u7ea7\uff0c\u5982\u679c\u5206\u6570\u672a\u572890\u300180\u300170\u8303\u56f4\u5185\uff0c\u5219\u8fd4\u56de’D’\u3002<\/p>\n
    \u793a\u4f8b2\uff1a\u5904\u7406NULL\u503c<\/strong><\/p>\n
    \u6709\u65f6\u5019\u6211\u4eec\u9700\u8981\u5bf9NULL\u503c\u8fdb\u884c\u7279\u6b8a\u5904\u7406\uff0c\u53ef\u4ee5\u4f7f\u7528DECODE\u51fd\u6570\u6765\u5904\u7406\uff0c\u4f8b\u5982\uff1a<\/p>\n
    SELECT student_name, DECODE(score,\n    NULL, '\u672a\u5f55\u5165',\n    score\n) AS new_score\nFROM student_table;<\/pre>\n
    \u8fd9\u6bb5\u4ee3\u7801\u4e2d\uff0c\u5982\u679c\u5206\u6570\u5b57\u6bb5\u4e3a\u7a7a\uff0c\u5219\u8fd4\u56de’\u672a\u5f55\u5165’\uff0c\u5426\u5219\u8fd4\u56de\u539f\u672c\u7684\u5206\u6570\u503c\u3002<\/p>\n
    \u901a\u8fc7\u4ee5\u4e0a\u793a\u4f8b\uff0c\u6211\u4eec\u53ef\u4ee5\u770b\u5230DECODE\u51fd\u6570\u5728\u5904\u7406\u590d\u6742\u7684\u6761\u4ef6\u5224\u65ad\u548c\u6570\u636e\u8f6c\u6362\u65f6\u5177\u6709\u5f88\u5927\u7684\u4f5c\u7528\uff0c\u80fd\u591f\u7b80\u6d01\u9ad8\u6548\u5730\u5b9e\u73b0\u6211\u4eec\u7684\u9700\u6c42\u3002<\/p>\n
    4. DECODE\u51fd\u6570\u7684\u5e94\u7528\u573a\u666f<\/h3>\n
    DECODE\u51fd\u6570\u5728\u5b9e\u9645\u5e94\u7528\u4e2d\u6709\u7740\u5e7f\u6cdb\u7684\u5e94\u7528\u573a\u666f\uff0c\u4e3b\u8981\u5305\u62ec\u4f46\u4e0d\u9650\u4e8e\u4ee5\u4e0b\u51e0\u4e2a\u65b9\u9762\uff1a<\/p>\n
      \n
    • \u6570\u636e\u6e05\u6d17\u548c\u8f6c\u6362\uff1a\u6839\u636e\u4e0d\u540c\u6761\u4ef6\u5bf9\u6570\u636e\u8fdb\u884c\u89c4\u8303\u5316\u5904\u7406\u3002<\/li>\n
    • \u6570\u636e\u5206\u6790\u548c\u62a5\u8868\u751f\u6210\uff1a\u6839\u636e\u4e0d\u540c\u7684\u6570\u636e\u6761\u4ef6\u751f\u6210\u4e0d\u540c\u7684\u62a5\u8868\u5185\u5bb9\u3002<\/li>\n
    • \u6570\u636e\u8f6c\u6362\u4e0e\u5408\u5e76\uff1a\u5c06\u4e0d\u540c\u6570\u636e\u6e90\u7684\u6570\u636e\u8f6c\u6362\u6210\u540c\u4e00\u89c4\u8303\u683c\u5f0f\u5e76\u5408\u5e76\u3002<\/li>\n<\/ul>\n
      \u603b\u7684\u6765\u8bf4\uff0cDECODE\u51fd\u6570\u662fOracle\u6570\u636e\u5e93\u4e2d\u4e00\u4e2a\u975e\u5e38\u5b9e\u7528\u7684\u51fd\u6570\uff0c\u80fd\u591f\u5e2e\u52a9\u6211\u4eec\u9ad8\u6548\u5730\u5904\u7406\u6570\u636e\uff0c\u5e76\u6839\u636e\u5177\u4f53\u7684\u6761\u4ef6\u8fd4\u56de\u76f8\u5e94\u7684\u7ed3\u679c\u503c\u3002\u901a\u8fc7\u672c\u6587\u7684\u4ecb\u7ecd\u548c\u793a\u4f8b\uff0c\u5e0c\u671b\u8bfb\u8005\u5bf9DECODE\u51fd\u6570\u6709\u4e86\u66f4\u6df1\u5165\u7684\u4e86\u89e3\uff0c\u5e76\u80fd\u5728\u5b9e\u9645\u5de5\u4f5c\u4e2d\u7075\u6d3b\u8fd0\u7528\u3002<\/p>\n
      \u4eca\u5929\u5173\u4e8e\u300a\u89e3\u6790Oracle DECODE\u51fd\u6570\u7684\u793a\u4f8b\u548c\u4f7f\u7528\u60c5\u51b5\u300b\u7684\u5185\u5bb9\u4ecb\u7ecd\u5c31\u5230\u6b64\u7ed3\u675f\uff0c\u5982\u679c\u6709\u4ec0\u4e48\u7591\u95ee\u6216\u8005\u5efa\u8bae\uff0c\u53ef\u4ee5\u5728\u4e3b\u673a\u5b9d\u8d1d\u516c\u4f17\u53f7\u4e0b\u591a\u591a\u56de\u590d\u4ea4\u6d41\uff1b\u6587\u4e2d\u82e5\u6709\u4e0d\u6b63\u4e4b\u5904\uff0c\u4e5f\u5e0c\u671b\u56de\u590d\u7559\u8a00\u4ee5\u544a\u77e5\uff01<\/p>\n
      \n
      \n <\/dt>\n<\/dl>\n","protected":false},"excerpt":{"rendered":"
      \u89e3\u6790Oracle DECODE\u51fd...<\/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-199835","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/199835","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=199835"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/199835\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=199835"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=199835"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=199835"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}