{"id":186240,"date":"2024-11-11T04:16:19","date_gmt":"2024-11-10T20:16:19","guid":{"rendered":"https:\/\/server.hk\/cnblog\/186240\/"},"modified":"2024-11-11T04:16:20","modified_gmt":"2024-11-10T20:16:20","slug":"%e6%95%b8%e6%93%9a%e5%ba%ab%e6%9f%a5%e8%a9%a2%e7%ad%86%e8%a9%a6%e9%a1%8c%e8%a7%a3%e6%9e%90%e5%a4%a7%e5%85%a8%ef%bc%88%e6%95%b8%e6%93%9a%e5%ba%ab%e6%9f%a5%e8%a9%a2%e7%ad%86%e8%a9%a6%e9%a1%8c%ef%bc%89","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/186240\/","title":{"rendered":"\u6578\u64da\u5eab\u67e5\u8a62\u7b46\u8a66\u984c\u89e3\u6790\u5927\u5168\uff08\u6578\u64da\u5eab\u67e5\u8a62\u7b46\u8a66\u984c\uff09"},"content":{"rendered":"

\u6578\u64da\u5eab\u67e5\u8a62\u7b46\u8a66\u984c\u89e3\u6790\u5927\u5168\uff08\u6578\u64da\u5eab\u67e5\u8a62\u7b46\u8a66\u984c\uff09<\/h1>\n

\u5728\u7576\u4eca\u7684\u6578\u64da\u9a45\u52d5\u6642\u4ee3\uff0c\u6578\u64da\u5eab\u67e5\u8a62\u7684\u80fd\u529b\u5c0d\u65bc\u4efb\u4f55\u4e00\u4f4d\u6578\u64da\u5c08\u696d\u4eba\u58eb\u4f86\u8aaa\u90fd\u662f\u81f3\u95dc\u91cd\u8981\u7684\u3002\u7121\u8ad6\u662f\u61c9\u8058\u6578\u64da\u5eab\u7ba1\u7406\u54e1\u3001\u6578\u64da\u5206\u6790\u5e2b\u9084\u662f\u8edf\u4ef6\u958b\u767c\u5de5\u7a0b\u5e2b\uff0c\u6578\u64da\u5eab\u67e5\u8a62\u7684\u7b46\u8a66\u984c\u76ee\u5f80\u5f80\u662f\u9762\u8a66\u904e\u7a0b\u4e2d\u7684\u4e00\u500b\u91cd\u8981\u74b0\u7bc0\u3002\u672c\u6587\u5c07\u6df1\u5165\u63a2\u8a0e\u4e00\u4e9b\u5e38\u898b\u7684\u6578\u64da\u5eab\u67e5\u8a62\u7b46\u8a66\u984c\uff0c\u4e26\u63d0\u4f9b\u8a73\u7d30\u7684\u89e3\u6790\u548c\u793a\u4f8b\u3002<\/p>\n

1. \u57fa\u672c\u67e5\u8a62<\/h2>\n

\u57fa\u672c\u67e5\u8a62\u662f\u6578\u64da\u5eab\u64cd\u4f5c\u7684\u57fa\u790e\uff0c\u901a\u5e38\u4f7f\u7528 SQL \u8a9e\u8a00\u4f86\u5be6\u73fe\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u7c21\u55ae\u7684\u67e5\u8a62\u793a\u4f8b\uff1a<\/p>\n

SELECT * FROM employees WHERE department = 'Sales';<\/code><\/pre>\n
\u9019\u689d\u67e5\u8a62\u5c07\u5f9e employees<\/code> \u8868\u4e2d\u9078\u64c7\u6240\u6709\u5c6c\u65bc\u300cSales\u300d\u90e8\u9580\u7684\u54e1\u5de5\u3002\u8003\u751f\u9700\u8981\u7406\u89e3 SQL \u8a9e\u6cd5\u7684\u57fa\u672c\u7d50\u69cb\uff0c\u5305\u62ec SELECT<\/code>\u3001FROM<\/code> \u548c WHERE<\/code> \u5b50\u53e5\u7684\u7528\u6cd5\u3002<\/p>\n
2. \u805a\u5408\u51fd\u6578<\/h2>\n
\u805a\u5408\u51fd\u6578\u7528\u65bc\u8a08\u7b97\u6578\u64da\u7684\u7e3d\u548c\u3001\u5e73\u5747\u503c\u3001\u6700\u5927\u503c\u548c\u6700\u5c0f\u503c\u7b49\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u4f7f\u7528\u805a\u5408\u51fd\u6578\u7684\u793a\u4f8b\uff1a<\/p>\n
SELECT COUNT(*) AS total_employees FROM employees;<\/code><\/pre>\n
\u9019\u689d\u67e5\u8a62\u5c07\u8fd4\u56de employees<\/code> \u8868\u4e2d\u7684\u54e1\u5de5\u7e3d\u6578\u3002\u8003\u751f\u61c9\u8a72\u719f\u6089\u5e38\u898b\u7684\u805a\u5408\u51fd\u6578\uff0c\u5982 COUNT<\/code>\u3001SUM<\/code>\u3001AVG<\/code>\u3001MAX<\/code> \u548c MIN<\/code>\uff0c\u4e26\u80fd\u5920\u5728\u4e0d\u540c\u7684\u60c5\u5883\u4e2d\u9748\u6d3b\u904b\u7528\u3002<\/p>\n
3. \u5206\u7d44\u67e5\u8a62<\/h2>\n
\u5206\u7d44\u67e5\u8a62\u901a\u5e38\u8207\u805a\u5408\u51fd\u6578\u4e00\u8d77\u4f7f\u7528\uff0c\u4ee5\u4fbf\u5c0d\u6578\u64da\u9032\u884c\u5206\u7d44\u548c\u8a08\u7b97\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u793a\u4f8b\uff1a<\/p>\n
SELECT department, COUNT(*) AS total_employees FROM employees GROUP BY department;<\/code><\/pre>\n
\u9019\u689d\u67e5\u8a62\u5c07\u6839\u64da\u90e8\u9580\u5c0d\u54e1\u5de5\u9032\u884c\u5206\u7d44\uff0c\u4e26\u8a08\u7b97\u6bcf\u500b\u90e8\u9580\u7684\u54e1\u5de5\u6578\u91cf\u3002\u8003\u751f\u9700\u8981\u7406\u89e3 GROUP BY<\/code> \u5b50\u53e5\u7684\u7528\u6cd5\uff0c\u4ee5\u53ca\u5982\u4f55\u8207\u805a\u5408\u51fd\u6578\u7d50\u5408\u4f7f\u7528\u3002<\/p>\n
4. \u9023\u63a5\u67e5\u8a62<\/h2>\n
\u9023\u63a5\u67e5\u8a62\u7528\u65bc\u5f9e\u591a\u500b\u8868\u4e2d\u6aa2\u7d22\u6578\u64da\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u5167\u9023\u63a5\u7684\u793a\u4f8b\uff1a<\/p>\n
SELECT e.name, d.department_name \nFROM employees e \nJOIN departments d ON e.department_id = d.id;<\/code><\/pre>\n
\u9019\u689d\u67e5\u8a62\u5c07\u8fd4\u56de\u54e1\u5de5\u7684\u59d3\u540d\u53ca\u5176\u6240\u5c6c\u90e8\u9580\u7684\u540d\u7a31\u3002\u8003\u751f\u61c9\u8a72\u719f\u6089\u4e0d\u540c\u985e\u578b\u7684\u9023\u63a5\uff08\u5982\u5167\u9023\u63a5\u3001\u5916\u9023\u63a5\uff09\u53ca\u5176\u7528\u6cd5\u3002<\/p>\n
5. \u5b50\u67e5\u8a62<\/h2>\n
\u5b50\u67e5\u8a62\u662f\u5d4c\u5957\u5728\u5176\u4ed6\u67e5\u8a62\u4e2d\u7684\u67e5\u8a62\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u5b50\u67e5\u8a62\u7684\u793a\u4f8b\uff1a<\/p>\n
SELECT name \nFROM employees \nWHERE department_id IN (SELECT id FROM departments WHERE location = 'New York');<\/code><\/pre>\n
\u9019\u689d\u67e5\u8a62\u5c07\u8fd4\u56de\u6240\u6709\u4f4d\u65bc\u300cNew York\u300d\u5730\u5340\u7684\u90e8\u9580\u4e2d\u7684\u54e1\u5de5\u59d3\u540d\u3002\u8003\u751f\u9700\u8981\u7406\u89e3\u5982\u4f55\u4f7f\u7528\u5b50\u67e5\u8a62\u4f86\u89e3\u6c7a\u66f4\u8907\u96dc\u7684\u67e5\u8a62\u9700\u6c42\u3002<\/p>\n
6. \u6578\u64da\u5eab\u8a2d\u8a08\u8207\u6b63\u898f\u5316<\/h2>\n
\u9664\u4e86\u67e5\u8a62\u8a9e\u8a00\uff0c\u8003\u751f\u9084\u61c9\u8a72\u4e86\u89e3\u6578\u64da\u5eab\u8a2d\u8a08\u7684\u57fa\u672c\u539f\u5247\uff0c\u5305\u62ec\u6b63\u898f\u5316\u7684\u6982\u5ff5\u3002\u6b63\u898f\u5316\u65e8\u5728\u6d88\u9664\u6578\u64da\u5197\u9918\uff0c\u78ba\u4fdd\u6578\u64da\u7684\u4e00\u81f4\u6027\u3002\u5e38\u898b\u7684\u6b63\u898f\u5316\u5f62\u5f0f\u5305\u62ec\u7b2c\u4e00\u8303\u5f0f\uff081NF\uff09\u3001\u7b2c\u4e8c\u8303\u5f0f\uff082NF\uff09\u548c\u7b2c\u4e09\u8303\u5f0f\uff083NF\uff09\u3002\u8003\u751f\u61c9\u8a72\u80fd\u5920\u89e3\u91cb\u9019\u4e9b\u8303\u5f0f\u7684\u7279\u9ede\u53ca\u5176\u5728\u6578\u64da\u5eab\u8a2d\u8a08\u4e2d\u7684\u61c9\u7528\u3002<\/p>\n
\u7e3d\u7d50<\/h2>\n
\u638c\u63e1\u6578\u64da\u5eab\u67e5\u8a62\u7684\u57fa\u672c\u6280\u80fd\u5c0d\u65bc\u4efb\u4f55\u6578\u64da\u5c08\u696d\u4eba\u58eb\u90fd\u662f\u5fc5\u4e0d\u53ef\u5c11\u7684\u3002\u901a\u904e\u7406\u89e3\u57fa\u672c\u67e5\u8a62\u3001\u805a\u5408\u51fd\u6578\u3001\u5206\u7d44\u67e5\u8a62\u3001\u9023\u63a5\u67e5\u8a62\u3001\u5b50\u67e5\u8a62\u4ee5\u53ca\u6578\u64da\u5eab\u8a2d\u8a08\u7684\u539f\u5247\uff0c\u8003\u751f\u53ef\u4ee5\u5728\u7b46\u8a66\u4e2d\u8868\u73fe\u51fa\u8272\u3002\u5c0d\u65bc\u5e0c\u671b\u5728\u9999\u6e2f\u5c0b\u627e\u9ad8\u6548\u80fd\u7684 VPS<\/a> \u89e3\u6c7a\u65b9\u6848\u7684\u7528\u6236\uff0cServer.HK \u63d0\u4f9b\u4e86\u591a\u7a2e\u9078\u64c7\uff0c\u6eff\u8db3\u4e0d\u540c\u9700\u6c42\u7684\u5ba2\u6236\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
\u5168\u9762\u89e3\u6790\u6578\u64da\u5eab\u67e5\u8a62\u7b46\u8a66\u984c\uff0c\u63d0\u4f9b\u8a73\u76e1\u89e3\u7b54\u8207\u6280\u5de7\uff0c\u52a9\u60a8\u8f15\u9b06\u61c9\u5c0d\u8003\u8a66\u6311\u6230\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-186240","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/186240","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=186240"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/186240\/revisions"}],"predecessor-version":[{"id":186241,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/186240\/revisions\/186241"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=186240"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=186240"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=186240"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}