{"id":199902,"date":"2025-05-06T09:35:17","date_gmt":"2025-05-06T01:35:17","guid":{"rendered":"https:\/\/server.hk\/cnblog\/199902\/"},"modified":"2025-05-06T09:35:17","modified_gmt":"2025-05-06T01:35:17","slug":"%e5%88%86%e6%9e%90oracle-decode%e5%87%bd%e6%95%b0%e7%9a%84%e7%94%a8%e6%b3%95%e5%8f%8a%e7%a4%ba%e4%be%8b%e6%83%85%e5%86%b5","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/199902\/","title":{"rendered":"\u5206\u6790Oracle DECODE\u51fd\u6570\u7684\u7528\u6cd5\u53ca\u793a\u4f8b\u60c5\u51b5"},"content":{"rendered":"

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

\u5206\u6790Oracle DECODE\u51fd\u6570\u7684\u7528\u6cd5\u53ca\u793a\u4f8b\u60c5\u51b5<\/h1>\n

\u4f60\u5728\u5b66\u4e60\u76f8\u5173\u7684\u77e5\u8bc6\u5417\uff1f\u672c\u6587\uff0c\u4e3b\u8981\u4ecb\u7ecd\u7684\u5185\u5bb9\u5c31\u6d89\u53ca\u5230\uff0c\u5982\u679c\u4f60\u60f3\u63d0\u5347\u81ea\u5df1\u7684\u5f00\u53d1\u80fd\u529b\uff0c\u5c31\u4e0d\u8981\u9519\u8fc7\u8fd9\u7bc7\u6587\u7ae0\uff0c\u5927\u5bb6\u8981\u77e5\u9053\u7f16\u7a0b\u7406\u8bba\u57fa\u7840\u548c\u5b9e\u6218\u64cd\u4f5c\u90fd\u662f\u4e0d\u53ef\u6216\u7f3a\u7684\u54e6\uff01<\/p>\n

Oracle DECODE\u51fd\u6570\u662f\u4e00\u79cd\u975e\u5e38\u5e38\u7528\u7684\u6761\u4ef6\u8868\u8fbe\u5f0f\u51fd\u6570\uff0c\u5176\u4e3b\u8981\u529f\u80fd\u662f\u6839\u636e\u6307\u5b9a\u7684\u6761\u4ef6\u5bf9\u8868\u8fbe\u5f0f\u7684\u7ed3\u679c\u8fdb\u884c\u8f6c\u6362\u5e76\u8fd4\u56de\u76f8\u5e94\u7684\u503c\u3002DECODE\u51fd\u6570\u7684\u8bed\u6cd5\u5982\u4e0b\uff1a<\/p>\n

DECODE(expr, search1, result1, search2, result2,...,default_result)<\/pre>\n
\u5176\u4e2d\uff0cexpr\u662f\u9700\u8981\u8fdb\u884c\u5224\u65ad\u7684\u8868\u8fbe\u5f0f\uff0csearch1\u3001search2…\u662f\u5f85\u5339\u914d\u7684\u6761\u4ef6\u503c\uff0cresult1\u3001result2…\u662f\u4e0e\u6761\u4ef6\u503c\u5339\u914d\u65f6\u9700\u8981\u8fd4\u56de\u7684\u7ed3\u679c\u503c\uff0cdefault_result\u662f\u5f53expr\u4e0e\u6240\u6709search\u503c\u5747\u4e0d\u5339\u914d\u65f6\u7684\u9ed8\u8ba4\u8fd4\u56de\u503c\u3002<\/p>\n
\u4e0b\u9762\u901a\u8fc7\u51e0\u4e2a\u5177\u4f53\u7684\u6848\u4f8b\u6765\u6f14\u793aDECODE\u51fd\u6570\u7684\u4f7f\u7528\u53ca\u5176\u5e94\u7528\u573a\u666f\u3002<\/p>\n
    \n
  1. \u6839\u636e\u6761\u4ef6\u503c\u8fd4\u56de\u56fa\u5b9a\u7ed3\u679c<\/strong><\/li>\n<\/ol>\n
    \u5047\u8bbe\u6211\u4eec\u6709\u4e00\u4e2a\u5458\u5de5\u8868Employee\uff0c\u8868\u4e2d\u5305\u542b\u5458\u5de5\u59d3\u540d\u548c\u5458\u5de5\u7b49\u7ea7\u4e24\u4e2a\u5b57\u6bb5\u3002\u6211\u4eec\u5e0c\u671b\u6839\u636e\u5458\u5de5\u7b49\u7ea7\u5b57\u6bb5\u7684\u503c\u8fd4\u56de\u5bf9\u5e94\u7684\u6587\u672c\u63cf\u8ff0\u3002\u53ef\u4ee5\u4f7f\u7528DECODE\u51fd\u6570\u6765\u5b9e\u73b0\uff1a<\/p>\n
    SELECT EmployeeName, DECODE(EmployeeLevel, 1, '\u521d\u7ea7\u5458\u5de5', 2, '\u4e2d\u7ea7\u5458\u5de5', 3, '\u9ad8\u7ea7\u5458\u5de5', '\u5176\u4ed6') AS LevelDescription\nFROM Employee;<\/pre>\n
    \u4ee5\u4e0aSQL\u8bed\u53e5\u4f1a\u5c06Employee\u8868\u4e2d\u7684\u5458\u5de5\u7b49\u7ea7\u5b57\u6bb5\u8f6c\u6362\u4e3a\u5bf9\u5e94\u7684\u6587\u672c\u63cf\u8ff0\uff0c\u5e76\u67e5\u8be2\u7ed3\u679c\u3002<\/p>\n
      \n
    1. \u5c06\u7a7a\u503c\u66ff\u6362\u4e3a\u9ed8\u8ba4\u503c<\/strong><\/li>\n<\/ol>\n
      \u6709\u65f6\u5019\u6211\u4eec\u9700\u8981\u5c06\u8868\u4e2d\u7684\u7a7a\u503c\u66ff\u6362\u4e3a\u9ed8\u8ba4\u503c\uff0c\u53ef\u4ee5\u4f7f\u7528DECODE\u51fd\u6570\u6765\u5904\u7406\uff1a<\/p>\n
      SELECT ProductName, DECODE(Price, NULL, 0, Price) AS ActualPrice\nFROM Product;<\/pre>\n
      \u4ee5\u4e0aSQL\u8bed\u53e5\u4f1a\u5c06Product\u8868\u4e2d\u7684Price\u5b57\u6bb5\u4e2d\u7684\u7a7a\u503c\u66ff\u6362\u4e3a0\uff0c\u5e76\u67e5\u8be2\u7ed3\u679c\u3002<\/p>\n
        \n
      1. \u591a\u6761\u4ef6\u5224\u65ad<\/strong><\/li>\n<\/ol>\n
        DECODE\u51fd\u6570\u4e5f\u53ef\u4ee5\u7528\u6765\u8fdb\u884c\u591a\u6761\u4ef6\u5224\u65ad\uff0c\u7c7b\u4f3c\u4e8e\u591a\u4e2aif-else\u6761\u4ef6\u5224\u65ad\u7684\u6548\u679c\u3002<\/p>\n
        SELECT OrderID, DECODE(Status, 1, '\u5f85\u5904\u7406', 2, '\u5904\u7406\u4e2d', 3, '\u5df2\u5b8c\u6210', '\u672a\u77e5\u72b6\u6001') AS OrderStatus\nFROM Orders;<\/pre>\n
        \u4ee5\u4e0aSQL\u8bed\u53e5\u4f1a\u6839\u636eOrders\u8868\u4e2d\u7684\u8ba2\u5355\u72b6\u6001\u5b57\u6bb5\u8fd4\u56de\u76f8\u5e94\u7684\u6587\u5b57\u63cf\u8ff0\uff0c\u5982\u679c\u72b6\u6001\u503c\u4e0d\u5728\u7ed9\u5b9a\u8303\u56f4\u5185\uff0c\u5219\u8fd4\u56de’\u672a\u77e5\u72b6\u6001’\u3002<\/p>\n
          \n
        1. \u5bf9\u6570\u636e\u8fdb\u884c\u5206\u7c7b<\/strong><\/li>\n<\/ol>\n
          DECODE\u51fd\u6570\u8fd8\u53ef\u4ee5\u7528\u6765\u5bf9\u6570\u636e\u8fdb\u884c\u5206\u7c7b\u5904\u7406\uff0c\u4f8b\u5982\u5c06\u6210\u7ee9\u5206\u4e3a\u4f18\u3001\u826f\u3001\u53ca\u683c\u3001\u4e0d\u53ca\u683c\u7b49\u7b49\u3002<\/p>\n
          SELECT StudentName, DECODE(Score,\n                          90, '\u4f18\u79c0',\n                          80, '\u826f\u597d',\n                          60, '\u53ca\u683c',\n                          '\u4e0d\u53ca\u683c') AS Grade\nFROM Student;<\/pre>\n
          \u4ee5\u4e0aSQL\u8bed\u53e5\u5c06Student\u8868\u4e2d\u7684\u6210\u7ee9\u5b57\u6bb5\u6309\u7167\u4e0d\u540c\u7684\u5206\u6570\u8303\u56f4\u8fdb\u884c\u5206\u7c7b\uff0c\u5e76\u8fd4\u56de\u5bf9\u5e94\u7684\u7b49\u7ea7\u3002<\/p>\n
          \u603b\u7684\u6765\u8bf4\uff0cOracle\u7684DECODE\u51fd\u6570\u975e\u5e38\u7075\u6d3b\uff0c\u53ef\u4ee5\u6839\u636e\u5177\u4f53\u7684\u9700\u6c42\u6765\u5bf9\u6570\u636e\u8fdb\u884c\u8f6c\u6362\u548c\u5904\u7406\uff0c\u63d0\u9ad8\u4e86SQL\u67e5\u8be2\u7684\u7075\u6d3b\u6027\u548c\u53ef\u8bfb\u6027\u3002\u5728\u5b9e\u9645\u5e94\u7528\u4e2d\uff0c\u53ef\u4ee5\u7ed3\u5408\u5176\u4ed6SQL\u51fd\u6570\u548c\u6761\u4ef6\u8868\u8fbe\u5f0f\u4e00\u8d77\u4f7f\u7528\uff0c\u5b9e\u73b0\u66f4\u4e30\u5bcc\u7684\u6570\u636e\u5904\u7406\u64cd\u4f5c\u3002<\/p>\n
          \u4ee5\u4e0a\u5c31\u662f\u300a\u5206\u6790Oracle DECODE\u51fd\u6570\u7684\u7528\u6cd5\u53ca\u793a\u4f8b\u60c5\u51b5\u300b\u7684\u8be6\u7ec6\u5185\u5bb9\uff0c\u66f4\u591a\u5173\u4e8eOracle,\u5206\u6790,DECODE\u7684\u8d44\u6599\u8bf7\u5173\u6ce8\u4e3b\u673a\u5b9d\u8d1d\u516c\u4f17\u53f7\uff01<\/p>\n
          \n
          \n <\/dt>\n<\/dl>\n","protected":false},"excerpt":{"rendered":"
          \u5206\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-199902","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/199902","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=199902"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/199902\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=199902"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=199902"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=199902"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}