{"id":20828,"date":"2024-01-02T06:37:23","date_gmt":"2024-01-02T06:37:23","guid":{"rendered":"https:\/\/server.hk\/blog\/20828\/"},"modified":"2024-11-14T10:37:50","modified_gmt":"2024-11-14T02:37:50","slug":"how-to-fix-postgresql-error-code-20000-case_not_found","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/20828\/","title":{"rendered":"\u5982\u4f55\u4fee\u5fa9 PostgreSQL \u932f\u8aa4\u4ee3\u78bc\uff1a20000 – case_not_found"},"content":{"rendered":"

\u5982\u4f55\u4fee\u5fa9 PostgreSQL \u932f\u8aa4\u4ee3\u78bc\uff1a20000 – case_not_found<\/h1>\n

PostgreSQL \u662f\u4e00\u6b3e\u529f\u80fd\u5f37\u5927\u7684\u958b\u6e90\u95dc\u806f\u5f0f\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\uff0c\u5ee3\u6cdb\u61c9\u7528\u65bc\u5404\u7a2e\u61c9\u7528\u3002\u7136\u800c\uff0c\u50cf\u6240\u6709\u8edf\u4ef6\u4e00\u6a23\uff0c\u5b83\u4e5f\u6703\u9047\u5230\u932f\u8aa4\u3002\u5176\u4e2d\u4e00\u500b\u5e38\u898b\u932f\u8aa4\u662f\u201ccase_not_found\u201d\uff0c\u5176\u932f\u8aa4\u4ee3\u78bc\u70ba 20000\u3002\u672c\u6587\u5c07\u63a2\u8a0e\u6b64\u932f\u8aa4\u7684\u542b\u7fa9\u4ee5\u53ca\u5982\u4f55\u4fee\u5fa9\u5b83\u3002<\/p>\n

\u4e86\u89e3 PostgreSQL \u932f\u8aa4\u4ee3\u78bc\uff1a20000 – case_not_found<\/h2>\n

\u932f\u8aa4\u4ee3\u78bc 20000 \u7684\u201ccase_not_found\u201d\u932f\u8aa4\u767c\u751f\u5728 PostgreSQL \u67e5\u8a62\u4e2d\u7684 CASE \u8a9e\u53e5\u7f3a\u5c11\u5c0d\u61c9\u7684 WHEN \u5b50\u53e5\u6642\u3002\u9019\u901a\u5e38\u8868\u793a\u67e5\u8a62\u6b63\u8a66\u5716\u8a55\u4f30\u4e00\u500b\u8207 CASE \u8a9e\u53e5\u4e2d\u6307\u5b9a\u7684\u689d\u4ef6\u5747\u4e0d\u76f8\u7b26\u7684\u503c\u3002<\/p>\n

\u4f8b\u5982\uff0c\u8003\u616e\u4ee5\u4e0b\u67e5\u8a62\uff1a<\/p>\n

SELECT\r\n  CASE\r\n    WHEN column = 'value1' THEN 'Result 1'\r\n    WHEN column = 'value2' THEN 'Result 2'\r\n  END\r\nFROM\r\n  table;\r\n<\/code><\/pre>\n
\u5982\u679c\u201ccolumn\u201d\u7684\u503c\u65e2\u4e0d\u7b49\u65bc ‘value1’ \u4e5f\u4e0d\u7b49\u65bc ‘value2’\uff0c\u5247\u67e5\u8a62\u5c07\u62cb\u51fa\u932f\u8aa4\u4ee3\u78bc 20000 \u7684\u201ccase_not_found\u201d\u932f\u8aa4\u3002<\/p>\n
\u4fee\u5fa9 PostgreSQL \u932f\u8aa4\u4ee3\u78bc\uff1a20000 – case_not_found<\/h2>\n
\u8981\u4fee\u5fa9\u201ccase_not_found\u201d\u932f\u8aa4\uff0c\u60a8\u9700\u8981\u78ba\u4fdd CASE \u8a9e\u53e5\u4e2d\u7684\u6240\u6709\u53ef\u80fd\u503c\u5747\u5728 WHEN \u5b50\u53e5\u4e2d\u5f97\u5230\u8986\u84cb\u3002\u4ee5\u4e0b\u662f\u5e7e\u500b\u53ef\u4ee5\u63a1\u53d6\u7684\u65b9\u6cd5\uff1a<\/p>\n
1. \u6dfb\u52a0\u9ed8\u8a8d\u7684 ELSE \u5b50\u53e5\uff1a<\/h3>\n
\u901a\u904e\u5728 CASE \u8a9e\u53e5\u4e2d\u6dfb\u52a0\u9ed8\u8a8d\u7684 ELSE \u5b50\u53e5\uff0c\u60a8\u53ef\u4ee5\u70ba\u672a\u6eff\u8db3\u4efb\u4f55\u6307\u5b9a\u689d\u4ef6\u7684\u60c5\u5f62\u63d0\u4f9b\u56de\u9000\u503c\u3002\u4f8b\u5982\uff1a<\/p>\n
SELECT\r\n  CASE\r\n    WHEN column = 'value1' THEN 'Result 1'\r\n    WHEN column = 'value2' THEN 'Result 2'\r\n    ELSE 'Default Result'\r\n  END\r\nFROM\r\n  table;\r\n<\/code><\/pre>\n
\u6709\u4e86\u9ed8\u8a8d\u7684 ELSE \u5b50\u53e5\uff0c\u5982\u679c\u201ccolumn\u201d\u7684\u503c\u4e0d\u5339\u914d ‘value1’ \u6216 ‘value2’\uff0c\u67e5\u8a62\u5c07\u8fd4\u56de ‘Default Result’\uff0c\u800c\u4e0d\u6703\u62cb\u51fa\u932f\u8aa4\u3002<\/p>\n
2. \u4f7f\u7528 NULL \u4f5c\u70ba\u9ed8\u8a8d\u503c\uff1a<\/h3>\n
\u60a8\u53ef\u4ee5\u5728 ELSE \u5b50\u53e5\u4e2d\u4f7f\u7528 NULL \u4f5c\u70ba\u9ed8\u8a8d\u503c\uff0c\u800c\u4e0d\u662f\u6307\u5b9a\u4e00\u500b\u9ed8\u8a8d\u7d50\u679c\u3002\u9019\u6a23\uff0c\u5728\u672a\u6eff\u8db3\u4efb\u4f55\u6307\u5b9a\u689d\u4ef6\u6642\uff0c\u67e5\u8a62\u5c07\u8fd4\u56de NULL\u3002\u4f8b\u5982\uff1a<\/p>\n
SELECT\r\n  CASE\r\n    WHEN column = 'value1' THEN 'Result 1'\r\n    WHEN column = 'value2' THEN 'Result 2'\r\n    ELSE NULL\r\n  END\r\nFROM\r\n  table;\r\n<\/code><\/pre>\n
\u4f7f\u7528 NULL \u4f5c\u70ba\u9ed8\u8a8d\u503c\u5728\u60a8\u5e0c\u671b\u5728\u61c9\u7528\u7a0b\u5f0f\u4ee3\u78bc\u4e2d\u55ae\u7368\u8655\u7406\u6b64\u60c5\u5f62\u6642\u5341\u5206\u6709\u7528\u3002<\/p>\n
3. \u6aa2\u67e5\u7f3a\u5931\u7684\u503c\uff1a<\/h3>\n
\u5982\u679c\u60a8\u7d93\u5e38\u9047\u5230\u201ccase_not_found\u201d\u932f\u8aa4\uff0c\u9019\u53ef\u80fd\u8868\u793a\u60a8\u6b63\u5728\u8a55\u4f30\u7684\u5217\u4e2d\u5b58\u5728\u7f3a\u5931\u7684\u503c\u3002\u5728\u9019\u7a2e\u60c5\u6cc1\u4e0b\uff0c\u60a8\u61c9\u8a72\u6aa2\u67e5\u6578\u64da\uff0c\u78ba\u4fdd CASE \u8a9e\u53e5\u4e2d\u8003\u616e\u5230\u6240\u6709\u53ef\u80fd\u7684\u503c\u3002<\/p>\n
\u901a\u904e\u9075\u5faa\u9019\u4e9b\u65b9\u6cd5\uff0c\u60a8\u53ef\u4ee5\u6709\u6548\u4fee\u5fa9 PostgreSQL \u932f\u8aa4\u4ee3\u78bc\uff1a20000 – case_not_found\uff0c\u4e26\u78ba\u4fdd\u60a8\u7684\u67e5\u8a62\u80fd\u8655\u7406\u6240\u6709\u53ef\u80fd\u7684\u60c5\u5883\u3002<\/p>\n
\u7e3d\u7d50\uff1a<\/h2>\n
\u9047\u5230 PostgreSQL \u932f\u8aa4\u4ee3\u78bc\uff1a20000 – case_not_found \u53ef\u80fd\u6703\u4ee4\u4eba\u6cae\u55aa\uff0c\u4f46\u9019\u662f\u4e00\u500b\u5e38\u898b\u554f\u984c\uff0c\u6613\u65bc\u89e3\u6c7a\u3002\u901a\u904e\u6dfb\u52a0\u9ed8\u8a8d\u7684 ELSE \u5b50\u53e5\u3001\u4f7f\u7528 NULL \u4f5c\u70ba\u9ed8\u8a8d\u503c\u6216\u6aa2\u67e5\u7f3a\u5931\u7684\u503c\uff0c\u60a8\u53ef\u4ee5\u4fee\u5fa9\u6b64\u932f\u8aa4\uff0c\u78ba\u4fdd\u67e5\u8a62\u9806\u5229\u904b\u884c\u3002\u5982\u679c\u60a8\u9700\u8981\u9032\u4e00\u6b65\u7684 PostgreSQL \u5e6b\u52a9\u6216\u4efb\u4f55\u5176\u4ed6 VPS \u8a17\u7ba1\u670d\u52d9\uff0c\u8acb\u8003\u616e\u806f\u7e6b Server.HK<\/a>\uff0c\u9019\u662f\u4e00\u5bb6\u63d0\u4f9b\u53ef\u9760\u548c\u9ad8\u6027\u80fd VPS \u89e3\u6c7a\u65b9\u6848\u7684\u9818\u5148\u4f9b\u61c9\u5546\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
\u5982\u4f55\u4fee\u5fa9 PostgreSQL ...<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4924],"tags":[],"class_list":["post-20828","post","type-post","status-publish","format-standard","hentry","category-setup-tutorials"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/20828","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=20828"}],"version-history":[{"count":2,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/20828\/revisions"}],"predecessor-version":[{"id":24252,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/20828\/revisions\/24252"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=20828"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=20828"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=20828"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}