{"id":61007,"date":"2024-10-13T07:39:24","date_gmt":"2024-10-12T23:39:24","guid":{"rendered":"https:\/\/server.hk\/cnblog\/61007\/"},"modified":"2024-10-13T07:39:24","modified_gmt":"2024-10-12T23:39:24","slug":"db2%e7%b5%82%e6%a5%b5sql%e6%80%a7%e8%83%bd%e8%aa%bf%e7%af%80%e6%8a%80%e8%a1%93%e7%b6%93%e5%85%b8%e7%89%88","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/61007\/","title":{"rendered":"DB2\u7d42\u6975SQL\u6027\u80fd\u8abf\u7bc0\u6280\u8853\u7d93\u5178\u7248"},"content":{"rendered":"

DB2\u7d42\u6975SQL\u6027\u80fd\u8abf\u7bc0\u6280\u8853\u7d93\u5178\u7248<\/h1>\n

\u5728\u7576\u4eca\u6578\u64da\u9a45\u52d5\u7684\u4e16\u754c\u4e2d\uff0c\u6578\u64da\u5eab\u7684\u6027\u80fd\u5c0d\u65bc\u4f01\u696d\u7684\u6210\u529f\u81f3\u95dc\u91cd\u8981\u3002IBM\u7684DB2\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\u4ee5\u5176\u5f37\u5927\u7684\u6027\u80fd\u548c\u9748\u6d3b\u6027\u800c\u805e\u540d\uff0c\u4f46\u8981\u5145\u5206\u767c\u63ee\u5176\u6f5b\u529b\uff0cSQL\u6027\u80fd\u8abf\u7bc0\u6280\u8853\u662f\u5fc5\u4e0d\u53ef\u5c11\u7684\u3002\u672c\u6587\u5c07\u63a2\u8a0e\u4e00\u4e9b\u7d93\u5178\u7684DB2 SQL\u6027\u80fd\u8abf\u7bc0\u6280\u8853\uff0c\u5e6b\u52a9\u7528\u6236\u512a\u5316\u67e5\u8a62\u6027\u80fd\uff0c\u63d0\u5347\u6574\u9ad4\u7cfb\u7d71\u6548\u7387\u3002<\/p>\n

1. \u7406\u89e3\u57f7\u884c\u8a08\u5283<\/h2>\n

\u57f7\u884c\u8a08\u5283\u662fDB2\u5982\u4f55\u57f7\u884cSQL\u67e5\u8a62\u7684\u8a73\u7d30\u6b65\u9a5f\u3002\u901a\u904e\u5206\u6790\u57f7\u884c\u8a08\u5283\uff0c\u7528\u6236\u53ef\u4ee5\u8b58\u5225\u6027\u80fd\u74f6\u9838\u3002\u4f7f\u7528\u4ee5\u4e0bSQL\u8a9e\u53e5\u53ef\u4ee5\u7372\u53d6\u67e5\u8a62\u7684\u57f7\u884c\u8a08\u5283\uff1a<\/p>\n

EXPLAIN PLAN FOR \nSELECT * FROM employees WHERE department = 'Sales';<\/code><\/pre>\n
\u57f7\u884c\u8a08\u5283\u7684\u5206\u6790\u53ef\u4ee5\u5e6b\u52a9\u7528\u6236\u4e86\u89e3DB2\u9078\u64c7\u7684\u8a2a\u554f\u8def\u5f91\uff0c\u4e26\u6839\u64da\u9700\u8981\u9032\u884c\u8abf\u6574\u3002<\/p>\n
2. \u4f7f\u7528\u7d22\u5f15<\/h2>\n
\u7d22\u5f15\u662f\u63d0\u9ad8\u67e5\u8a62\u6027\u80fd\u7684\u95dc\u9375\u3002\u9069\u7576\u7684\u7d22\u5f15\u53ef\u4ee5\u986f\u8457\u6e1b\u5c11\u67e5\u8a62\u7684\u57f7\u884c\u6642\u9593\u3002\u7528\u6236\u61c9\u6839\u64da\u67e5\u8a62\u7684\u7279\u6027\u9078\u64c7\u5408\u9069\u7684\u7d22\u5f15\u985e\u578b\uff0c\u4f8b\u5982B\u6a39\u7d22\u5f15\u6216\u4f4d\u5716\u7d22\u5f15\u3002\u4ee5\u4e0b\u662f\u5275\u5efa\u7d22\u5f15\u7684\u793a\u4f8b\uff1a<\/p>\n
CREATE INDEX idx_department ON employees(department);<\/code><\/pre>\n
\u5728\u9078\u64c7\u7d22\u5f15\u6642\uff0c\u61c9\u8003\u616e\u5230\u67e5\u8a62\u7684\u983b\u7387\u548c\u6578\u64da\u7684\u66f4\u65b0\u983b\u7387\uff0c\u4ee5\u907f\u514d\u904e\u591a\u7684\u7d22\u5f15\u5c0e\u81f4\u6027\u80fd\u4e0b\u964d\u3002<\/p>\n
3. SQL\u67e5\u8a62\u91cd\u5beb<\/h2>\n
\u6709\u6642\u5019\uff0c\u7c21\u55ae\u7684SQL\u67e5\u8a62\u91cd\u5beb\u53ef\u4ee5\u986f\u8457\u63d0\u9ad8\u6027\u80fd\u3002\u4f8b\u5982\uff0c\u4f7f\u7528JOIN\u800c\u4e0d\u662f\u5b50\u67e5\u8a62\uff0c\u6216\u4f7f\u7528UNION ALL\u800c\u4e0d\u662fUNION\u3002\u4ee5\u4e0b\u662f\u91cd\u5beb\u67e5\u8a62\u7684\u793a\u4f8b\uff1a<\/p>\n
-- \u539f\u59cb\u67e5\u8a62\nSELECT * FROM employees WHERE department IN (SELECT department FROM departments WHERE location = 'New York');\n\n-- \u91cd\u5beb\u67e5\u8a62\nSELECT e.* FROM employees e JOIN departments d ON e.department = d.department WHERE d.location = 'New York';<\/code><\/pre>\n
\u9019\u6a23\u7684\u91cd\u5beb\u4e0d\u50c5\u63d0\u9ad8\u4e86\u53ef\u8b80\u6027\uff0c\u9084\u80fd\u63d0\u9ad8\u67e5\u8a62\u6027\u80fd\u3002<\/p>\n
4. \u8abf\u6574DB2\u914d\u7f6e\u53c3\u6578<\/h2>\n
DB2\u63d0\u4f9b\u4e86\u591a\u7a2e\u914d\u7f6e\u53c3\u6578\uff0c\u9019\u4e9b\u53c3\u6578\u53ef\u4ee5\u5f71\u97ff\u67e5\u8a62\u6027\u80fd\u3002\u4f8b\u5982\uff0c\u8abf\u6574\u5167\u5b58\u5206\u914d\u3001\u4e26\u884c\u8655\u7406\u548c\u7de9\u5b58\u5927\u5c0f\u7b49\u53c3\u6578\uff0c\u53ef\u4ee5\u986f\u8457\u63d0\u9ad8\u6027\u80fd\u3002\u7528\u6236\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u547d\u4ee4\u67e5\u770b\u7576\u524d\u7684\u914d\u7f6e\u53c3\u6578\uff1a<\/p>\n
GET DATABASE CONFIGURATION;<\/code><\/pre>\n
\u6839\u64da\u5be6\u969b\u9700\u6c42\u8abf\u6574\u9019\u4e9b\u53c3\u6578\uff0c\u53ef\u4ee5\u4f7fDB2\u5728\u7279\u5b9a\u5de5\u4f5c\u8ca0\u8f09\u4e0b\u904b\u884c\u5f97\u66f4\u9ad8\u6548\u3002<\/p>\n
5. \u5b9a\u671f\u7dad\u8b77\u6578\u64da\u5eab<\/h2>\n
\u5b9a\u671f\u7684\u6578\u64da\u5eab\u7dad\u8b77\u662f\u78ba\u4fdd\u6027\u80fd\u7a69\u5b9a\u7684\u91cd\u8981\u63aa\u65bd\u3002\u9019\u5305\u62ec\u91cd\u7d44\u6578\u64da\u3001\u66f4\u65b0\u7d71\u8a08\u4fe1\u606f\u548c\u6e05\u7406\u4e0d\u5fc5\u8981\u7684\u6578\u64da\u3002\u7528\u6236\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u547d\u4ee4\u66f4\u65b0\u7d71\u8a08\u4fe1\u606f\uff1a<\/p>\n
RUNSTATS ON TABLE employees;<\/code><\/pre>\n
\u9019\u6a23\u53ef\u4ee5\u5e6b\u52a9DB2\u66f4\u597d\u5730\u9078\u64c7\u57f7\u884c\u8a08\u5283\uff0c\u5f9e\u800c\u63d0\u9ad8\u67e5\u8a62\u6027\u80fd\u3002<\/p>\n
\u7e3d\u7d50<\/h2>\n
DB2\u7684SQL\u6027\u80fd\u8abf\u7bc0\u662f\u4e00\u500b\u6301\u7e8c\u7684\u904e\u7a0b\uff0c\u901a\u904e\u7406\u89e3\u57f7\u884c\u8a08\u5283\u3001\u4f7f\u7528\u7d22\u5f15\u3001\u91cd\u5beb\u67e5\u8a62\u3001\u8abf\u6574\u914d\u7f6e\u53c3\u6578\u4ee5\u53ca\u5b9a\u671f\u7dad\u8b77\u6578\u64da\u5eab\uff0c\u7528\u6236\u53ef\u4ee5\u986f\u8457\u63d0\u9ad8\u67e5\u8a62\u6027\u80fd\u3002\u9019\u4e9b\u6280\u8853\u4e0d\u50c5\u9069\u7528\u65bcDB2\uff0c\u4e5f\u53ef\u4ee5\u61c9\u7528\u65bc\u5176\u4ed6\u6578\u64da\u5eab\u7cfb\u7d71\u3002\u5c0d\u65bc\u9700\u8981\u9ad8\u6548\u6578\u64da\u8655\u7406\u7684\u4f01\u696d\uff0c\u9078\u64c7\u5408\u9069\u7684 VPS<\/a> \u89e3\u6c7a\u65b9\u6848\u548c\u512a\u5316\u6578\u64da\u5eab\u6027\u80fd\u540c\u6a23\u91cd\u8981\u3002\u4e86\u89e3\u66f4\u591a\u95dc\u65bc \u9999\u6e2fVPS<\/a> \u548c \u4e91\u670d\u52a1\u5668<\/a> \u7684\u4fe1\u606f\uff0c\u8acb\u8a2a\u554f\u6211\u5011\u7684\u7db2\u7ad9\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
\u63a2\u7d22\u300aDB2\u7d42\u6975SQL\u6027\u80fd\u8abf\u7bc0\u6280\u8853\u7d93\u5178\u7248\u300b\uff0c\u638c\u63e1\u9ad8\u6548SQL\u8abf\u512a\u6280\u5de7\uff0c\u63d0\u5347\u6578\u64da\u5eab\u6027\u80fd\uff0c\u5be6\u73fe\u6700\u4f73\u6548\u80fd\u3002<\/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-61007","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/61007","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=61007"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/61007\/revisions"}],"predecessor-version":[{"id":61008,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/61007\/revisions\/61008"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=61007"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=61007"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=61007"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}