{"id":143757,"date":"2024-11-01T00:59:21","date_gmt":"2024-10-31T16:59:21","guid":{"rendered":"https:\/\/server.hk\/cnblog\/143757\/"},"modified":"2024-11-01T00:59:22","modified_gmt":"2024-10-31T16:59:22","slug":"sql-%e6%9f%a5%e8%a9%a2%e7%a9%ba%e8%a1%a8%e7%9a%84%e6%96%b9%e6%b3%95%ef%bc%88sql-%e6%9f%a5%e8%a9%a2%e6%95%b8%e6%93%9a%e5%ba%ab%e4%b8%ad%e7%a9%ba%e8%a1%a8%ef%bc%89","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/143757\/","title":{"rendered":"SQL \u67e5\u8a62\u7a7a\u8868\u7684\u65b9\u6cd5\uff08sql \u67e5\u8a62\u6578\u64da\u5eab\u4e2d\u7a7a\u8868\uff09"},"content":{"rendered":"

SQL \u67e5\u8a62\u7a7a\u8868\u7684\u65b9\u6cd5\uff08SQL \u67e5\u8a62\u6578\u64da\u5eab\u4e2d\u7a7a\u8868\uff09<\/h1>\n

\u5728\u6578\u64da\u5eab\u7ba1\u7406\u4e2d\uff0c\u67e5\u8a62\u7a7a\u8868\u662f\u4e00\u500b\u5e38\u898b\u7684\u9700\u6c42\u3002\u7121\u8ad6\u662f\u70ba\u4e86\u6e05\u7406\u6578\u64da\u3001\u9032\u884c\u6578\u64da\u5206\u6790\uff0c\u9084\u662f\u70ba\u4e86\u7dad\u8b77\u6578\u64da\u5eab\u7684\u6574\u9ad4\u5065\u5eb7\uff0c\u4e86\u89e3\u5982\u4f55\u6709\u6548\u5730\u67e5\u8a62\u7a7a\u8868\u90fd\u662f\u975e\u5e38\u91cd\u8981\u7684\u3002\u672c\u6587\u5c07\u4ecb\u7d39\u5e7e\u7a2e\u5728 SQL \u4e2d\u67e5\u8a62\u7a7a\u8868\u7684\u65b9\u6cd5\uff0c\u4e26\u63d0\u4f9b\u76f8\u61c9\u7684\u793a\u4f8b\u4ee3\u78bc\u3002<\/p>\n

\u4ec0\u9ebc\u662f\u7a7a\u8868\uff1f<\/h2>\n

\u7a7a\u8868\u662f\u6307\u5728\u6578\u64da\u5eab\u4e2d\u5b58\u5728\u4f46\u4e0d\u5305\u542b\u4efb\u4f55\u6578\u64da\u7684\u8868\u3002\u9019\u610f\u5473\u8457\u8a72\u8868\u7684\u884c\u6578\u70ba\u96f6\u3002\u7a7a\u8868\u53ef\u80fd\u662f\u7531\u65bc\u6578\u64da\u522a\u9664\u3001\u6578\u64da\u5c0e\u5165\u5931\u6557\u6216\u5176\u4ed6\u539f\u56e0\u9020\u6210\u7684\u3002\u67e5\u8a62\u9019\u4e9b\u7a7a\u8868\u53ef\u4ee5\u5e6b\u52a9\u6578\u64da\u5eab\u7ba1\u7406\u54e1\u4e86\u89e3\u6578\u64da\u5eab\u7684\u72c0\u614b\uff0c\u4e26\u9032\u884c\u5fc5\u8981\u7684\u7dad\u8b77\u3002<\/p>\n

\u67e5\u8a62\u7a7a\u8868\u7684\u57fa\u672c\u65b9\u6cd5<\/h2>\n

\u5728 SQL \u4e2d\uff0c\u67e5\u8a62\u7a7a\u8868\u7684\u6700\u76f4\u63a5\u65b9\u6cd5\u662f\u4f7f\u7528 SELECT<\/code> \u8a9e\u53e5\u7d50\u5408 COUNT<\/code> \u51fd\u6578\u3002\u4ee5\u4e0b\u662f\u67e5\u8a62\u7279\u5b9a\u8868\u662f\u5426\u70ba\u7a7a\u7684\u57fa\u672c\u8a9e\u6cd5\uff1a<\/p>\n

SELECT COUNT(*) FROM \u8868\u540d;<\/code><\/pre>\n
\u5982\u679c\u8fd4\u56de\u7684\u7d50\u679c\u70ba 0\uff0c\u5247\u8a72\u8868\u70ba\u7a7a\u3002\u4f8b\u5982\uff0c\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u540d\u70ba users<\/code> \u7684\u8868\uff0c\u6211\u5011\u53ef\u4ee5\u9019\u6a23\u67e5\u8a62\uff1a<\/p>\n
SELECT COUNT(*) FROM users;<\/code><\/pre>\n
\u5982\u679c\u7d50\u679c\u70ba 0\uff0c\u5247\u8868\u793a users<\/code> \u8868\u662f\u7a7a\u7684\u3002<\/p>\n
\u67e5\u8a62\u6240\u6709\u7a7a\u8868<\/h2>\n
\u5982\u679c\u60a8\u60f3\u67e5\u8a62\u6578\u64da\u5eab\u4e2d\u6240\u6709\u7684\u7a7a\u8868\uff0c\u53ef\u4ee5\u4f7f\u7528\u7cfb\u7d71\u76ee\u9304\u6216\u4fe1\u606f\u67b6\u69cb\u4f86\u7372\u53d6\u9019\u4e9b\u4fe1\u606f\u3002\u4ee5\u4e0b\u662f\u91dd\u5c0d MySQL \u548c PostgreSQL \u7684\u793a\u4f8b\uff1a<\/p>\n
MySQL<\/h3>\n
SELECT TABLE_NAME \nFROM information_schema.tables \nWHERE TABLE_SCHEMA = '\u6578\u64da\u5eab\u540d' \nAND TABLE_ROWS = 0;<\/code><\/pre>\n
\u9019\u6bb5 SQL \u8a9e\u53e5\u5c07\u8fd4\u56de\u6307\u5b9a\u6578\u64da\u5eab\u4e2d\u6240\u6709\u884c\u6578\u70ba 0 \u7684\u8868\u540d\u3002<\/p>\n
PostgreSQL<\/h3>\n
SELECT table_name \nFROM information_schema.tables \nWHERE table_schema = 'public' \nAND table_type = 'BASE TABLE' \nAND (SELECT COUNT(*) FROM table_name) = 0;<\/code><\/pre>\n
\u5728 PostgreSQL \u4e2d\uff0c\u60a8\u9700\u8981\u4f7f\u7528\u5b50\u67e5\u8a62\u4f86\u6aa2\u67e5\u6bcf\u500b\u8868\u7684\u884c\u6578\u3002<\/p>\n
\u4f7f\u7528\u5b58\u5132\u904e\u7a0b\u67e5\u8a62\u7a7a\u8868<\/h2>\n
\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\uff0c\u60a8\u53ef\u80fd\u5e0c\u671b\u5c07\u67e5\u8a62\u7a7a\u8868\u7684\u908f\u8f2f\u5c01\u88dd\u5728\u5b58\u5132\u904e\u7a0b\u4e2d\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u7c21\u55ae\u7684 MySQL \u5b58\u5132\u904e\u7a0b\u793a\u4f8b\uff1a<\/p>\n
DELIMITER \/\/\nCREATE PROCEDURE GetEmptyTables(IN dbName VARCHAR(255))\nBEGIN\n    SELECT TABLE_NAME \n    FROM information_schema.tables \n    WHERE TABLE_SCHEMA = dbName \n    AND TABLE_ROWS = 0;\nEND \/\/\nDELIMITER ;<\/code><\/pre>\n
\u9019\u500b\u5b58\u5132\u904e\u7a0b\u63a5\u53d7\u4e00\u500b\u6578\u64da\u5eab\u540d\u7a31\u4f5c\u70ba\u53c3\u6578\uff0c\u4e26\u8fd4\u56de\u8a72\u6578\u64da\u5eab\u4e2d\u6240\u6709\u7a7a\u8868\u7684\u540d\u7a31\u3002<\/p>\n
\u7d50\u8ad6<\/h2>\n
\u67e5\u8a62\u7a7a\u8868\u5728\u6578\u64da\u5eab\u7ba1\u7406\u4e2d\u662f\u4e00\u9805\u91cd\u8981\u7684\u6280\u80fd\u3002\u7121\u8ad6\u662f\u4f7f\u7528\u57fa\u672c\u7684 SELECT<\/code> \u8a9e\u53e5\uff0c\u9084\u662f\u5229\u7528\u7cfb\u7d71\u76ee\u9304\u548c\u5b58\u5132\u904e\u7a0b\uff0c\u4e86\u89e3\u5982\u4f55\u6709\u6548\u5730\u67e5\u8a62\u7a7a\u8868\u90fd\u80fd\u5e6b\u52a9\u60a8\u66f4\u597d\u5730\u7ba1\u7406\u6578\u64da\u5eab\u3002\u901a\u904e\u9019\u4e9b\u65b9\u6cd5\uff0c\u60a8\u53ef\u4ee5\u8f15\u9b06\u8b58\u5225\u548c\u8655\u7406\u7a7a\u8868\uff0c\u5f9e\u800c\u4fdd\u6301\u6578\u64da\u5eab\u7684\u6574\u9ad4\u5065\u5eb7\u3002<\/p>\n
\u5982\u679c\u60a8\u6b63\u5728\u5c0b\u627e\u9ad8\u6548\u7684 VPS<\/a> \u89e3\u6c7a\u65b9\u6848\u4f86\u904b\u884c\u60a8\u7684\u6578\u64da\u5eab\uff0cServer.HK \u63d0\u4f9b\u591a\u7a2e\u9078\u64c7\uff0c\u6eff\u8db3\u4e0d\u540c\u9700\u6c42\u7684\u5ba2\u6236\u3002\u7121\u8ad6\u662f \u9999\u6e2fVPS<\/a> \u9084\u662f\u5176\u4ed6\u670d\u52d9\uff0c\u6211\u5011\u90fd\u80fd\u70ba\u60a8\u63d0\u4f9b\u652f\u6301\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
\u4e86\u89e3\u5982\u4f55\u4f7f\u7528 SQL \u67e5\u8a62\u6578\u64da\u5eab\u4e2d\u7684\u7a7a\u8868\uff0c\u638c\u63e1\u6709\u6548\u6aa2\u67e5\u8868\u662f\u5426\u7121\u6578\u64da\u7684\u6280\u5de7\u8207\u65b9\u6cd5\u3002<\/p>\n","protected":false},"author":0,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-143757","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/143757","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"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=143757"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/143757\/revisions"}],"predecessor-version":[{"id":143758,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/143757\/revisions\/143758"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=143757"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=143757"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=143757"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}