{"id":191838,"date":"2024-11-12T17:15:19","date_gmt":"2024-11-12T09:15:19","guid":{"rendered":"https:\/\/server.hk\/cnblog\/191838\/"},"modified":"2024-11-12T17:15:21","modified_gmt":"2024-11-12T09:15:21","slug":"%e8%a9%b3%e8%a7%a3sql%e9%82%8f%e8%bc%af%e6%9f%a5%e8%a9%a2%e7%9a%84%e5%90%84%e5%80%8b%e9%9a%8e%e6%ae%b5","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/191838\/","title":{"rendered":"\u8a73\u89e3SQL\u908f\u8f2f\u67e5\u8a62\u7684\u5404\u500b\u968e\u6bb5"},"content":{"rendered":"

\u8a73\u89e3SQL\u908f\u8f2f\u67e5\u8a62\u7684\u5404\u500b\u968e\u6bb5<\/h1>\n

SQL\uff08\u7d50\u69cb\u5316\u67e5\u8a62\u8a9e\u8a00\uff09\u662f\u7528\u65bc\u7ba1\u7406\u548c\u64cd\u4f5c\u95dc\u4fc2\u578b\u6578\u64da\u5eab\u7684\u6a19\u6e96\u8a9e\u8a00\u3002\u5728\u57f7\u884cSQL\u67e5\u8a62\u6642\uff0c\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\uff08DBMS\uff09\u6703\u7d93\u6b77\u4e00\u7cfb\u5217\u7684\u908f\u8f2f\u67e5\u8a62\u968e\u6bb5\u3002\u9019\u4e9b\u968e\u6bb5\u78ba\u4fdd\u67e5\u8a62\u80fd\u5920\u9ad8\u6548\u4e14\u6b63\u78ba\u5730\u57f7\u884c\u3002\u672c\u6587\u5c07\u6df1\u5165\u63a2\u8a0eSQL\u908f\u8f2f\u67e5\u8a62\u7684\u5404\u500b\u968e\u6bb5\uff0c\u5e6b\u52a9\u8b80\u8005\u66f4\u597d\u5730\u7406\u89e3\u5176\u904b\u4f5c\u539f\u7406\u3002<\/p>\n

1. \u67e5\u8a62\u89e3\u6790\uff08Parsing\uff09<\/h2>\n

\u67e5\u8a62\u89e3\u6790\u662fSQL\u67e5\u8a62\u7684\u7b2c\u4e00\u500b\u968e\u6bb5\u3002\u5728\u9019\u500b\u968e\u6bb5\uff0cDBMS\u6703\u5c0d\u8f38\u5165\u7684SQL\u8a9e\u53e5\u9032\u884c\u8a9e\u6cd5\u6aa2\u67e5\uff0c\u78ba\u4fdd\u5176\u7b26\u5408SQL\u8a9e\u6cd5\u898f\u7bc4\u3002\u5982\u679c\u67e5\u8a62\u8a9e\u53e5\u5b58\u5728\u8a9e\u6cd5\u932f\u8aa4\uff0c\u7cfb\u7d71\u5c07\u8fd4\u56de\u932f\u8aa4\u4fe1\u606f\uff0c\u4e26\u7d42\u6b62\u57f7\u884c\u3002<\/p>\n

\u4f8b\u5982\uff0c\u4ee5\u4e0b\u67e5\u8a62\u8a9e\u53e5\u5c07\u6703\u88ab\u89e3\u6790\uff1a<\/p>\n

SELECT * FROM users WHERE age > 18;<\/code><\/pre>\n
\u5982\u679c\u8a9e\u6cd5\u6b63\u78ba\uff0c\u7cfb\u7d71\u5c07\u751f\u6210\u4e00\u500b\u89e3\u6790\u6a39\uff08Parse Tree\uff09\uff0c\u9019\u662f\u4e00\u7a2e\u6a39\u72c0\u7d50\u69cb\uff0c\u8868\u793a\u67e5\u8a62\u7684\u8a9e\u6cd5\u7d50\u69cb\u3002<\/p>\n
2. \u67e5\u8a62\u512a\u5316\uff08Optimization\uff09<\/h2>\n
\u5728\u67e5\u8a62\u512a\u5316\u968e\u6bb5\uff0cDBMS\u6703\u5206\u6790\u89e3\u6790\u6a39\u4e26\u751f\u6210\u57f7\u884c\u8a08\u5283\u3002\u9019\u500b\u8a08\u5283\u662f\u6839\u64da\u6578\u64da\u5eab\u7684\u7d71\u8a08\u4fe1\u606f\u548c\u7d22\u5f15\u4f86\u6c7a\u5b9a\u7684\uff0c\u76ee\u7684\u662f\u9078\u64c7\u6700\u6709\u6548\u7684\u57f7\u884c\u8def\u5f91\u3002\u512a\u5316\u5668\u6703\u8003\u616e\u591a\u7a2e\u56e0\u7d20\uff0c\u4f8b\u5982\u8868\u7684\u5927\u5c0f\u3001\u7d22\u5f15\u7684\u5b58\u5728\u8207\u5426\u3001\u4ee5\u53ca\u904e\u53bb\u67e5\u8a62\u7684\u6027\u80fd\u7b49\u3002<\/p>\n
\u4f8b\u5982\uff0c\u5c0d\u65bc\u4ee5\u4e0b\u67e5\u8a62\uff1a<\/p>\n
SELECT name FROM users WHERE age > 18 ORDER BY name;<\/code><\/pre>\n
\u512a\u5316\u5668\u53ef\u80fd\u6703\u9078\u64c7\u4f7f\u7528\u7d22\u5f15\u4f86\u52a0\u901f\u67e5\u8a62\uff0c\u7279\u5225\u662f\u7576\u201cage\u201d\u5b57\u6bb5\u6709\u7d22\u5f15\u6642\u3002<\/p>\n
3. \u57f7\u884c\u8a08\u5283\u751f\u6210\uff08Execution Plan Generation\uff09<\/h2>\n
\u5728\u9019\u500b\u968e\u6bb5\uff0cDBMS\u6839\u64da\u512a\u5316\u5668\u751f\u6210\u7684\u57f7\u884c\u8a08\u5283\uff0c\u6e96\u5099\u5be6\u969b\u57f7\u884c\u67e5\u8a62\u3002\u57f7\u884c\u8a08\u5283\u5305\u542b\u4e86\u5177\u9ad4\u7684\u64cd\u4f5c\u6b65\u9a5f\uff0c\u4f8b\u5982\u5982\u4f55\u8a2a\u554f\u6578\u64da\u3001\u5982\u4f55\u904e\u6ffe\u6578\u64da\u3001\u4ee5\u53ca\u5982\u4f55\u6392\u5e8f\u7b49\u3002<\/p>\n
\u57f7\u884c\u8a08\u5283\u901a\u5e38\u6703\u4ee5\u4e00\u7a2e\u53ef\u8996\u5316\u7684\u65b9\u5f0f\u5448\u73fe\uff0c\u958b\u767c\u8005\u53ef\u4ee5\u901a\u904e\u6578\u64da\u5eab\u7ba1\u7406\u5de5\u5177\u67e5\u770b\u9019\u4e9b\u8a08\u5283\uff0c\u4ee5\u4fbf\u9032\u884c\u6027\u80fd\u8abf\u512a\u3002<\/p>\n
4. \u67e5\u8a62\u57f7\u884c\uff08Execution\uff09<\/h2>\n
\u5728\u67e5\u8a62\u57f7\u884c\u968e\u6bb5\uff0cDBMS\u6839\u64da\u751f\u6210\u7684\u57f7\u884c\u8a08\u5283\u5be6\u969b\u57f7\u884c\u67e5\u8a62\u3002\u9019\u5305\u62ec\u5f9e\u78c1\u789f\u4e2d\u8b80\u53d6\u6578\u64da\u3001\u904e\u6ffe\u4e0d\u7b26\u5408\u689d\u4ef6\u7684\u6578\u64da\u3001\u4ee5\u53ca\u9032\u884c\u6392\u5e8f\u7b49\u64cd\u4f5c\u3002\u57f7\u884c\u904e\u7a0b\u4e2d\uff0cDBMS\u6703\u5c07\u7d50\u679c\u5b58\u5132\u5728\u5167\u5b58\u4e2d\uff0c\u4e26\u6700\u7d42\u8fd4\u56de\u7d66\u7528\u6236\u3002<\/p>\n
\u4f8b\u5982\uff0c\u5c0d\u65bc\u4e0a\u8ff0\u67e5\u8a62\uff0cDBMS\u5c07\u5f9e\u201cusers\u201d\u8868\u4e2d\u8b80\u53d6\u6240\u6709\u5e74\u9f61\u5927\u65bc18\u7684\u7528\u6236\uff0c\u4e26\u6839\u64da\u540d\u5b57\u9032\u884c\u6392\u5e8f\uff0c\u7136\u5f8c\u8fd4\u56de\u7d50\u679c\u96c6\u3002<\/p>\n
5. \u7d50\u679c\u8fd4\u56de\uff08Result Return\uff09<\/h2>\n
\u6700\u5f8c\uff0c\u67e5\u8a62\u7d50\u679c\u5c07\u88ab\u8fd4\u56de\u7d66\u7528\u6236\u3002\u9019\u4e9b\u7d50\u679c\u53ef\u4ee5\u662f\u55ae\u4e00\u7684\u6578\u64da\u884c\u3001\u6578\u64da\u96c6\uff0c\u6216\u662f\u7d71\u8a08\u4fe1\u606f\u7b49\u3002\u7528\u6236\u53ef\u4ee5\u6839\u64da\u9019\u4e9b\u7d50\u679c\u9032\u884c\u9032\u4e00\u6b65\u7684\u64cd\u4f5c\u6216\u5206\u6790\u3002<\/p>\n
\u7e3d\u7d50<\/h2>\n
SQL\u908f\u8f2f\u67e5\u8a62\u7684\u5404\u500b\u968e\u6bb5\u5305\u62ec\u67e5\u8a62\u89e3\u6790\u3001\u67e5\u8a62\u512a\u5316\u3001\u57f7\u884c\u8a08\u5283\u751f\u6210\u3001\u67e5\u8a62\u57f7\u884c\u548c\u7d50\u679c\u8fd4\u56de\u3002\u4e86\u89e3\u9019\u4e9b\u968e\u6bb5\u6709\u52a9\u65bc\u958b\u767c\u8005\u64b0\u5beb\u66f4\u9ad8\u6548\u7684\u67e5\u8a62\uff0c\u4e26\u9032\u884c\u6027\u80fd\u8abf\u512a\u3002\u5c0d\u65bc\u9700\u8981\u9ad8\u6548\u6578\u64da\u8655\u7406\u7684\u61c9\u7528\uff0c\u9078\u64c7\u5408\u9069\u7684\u6578\u64da\u5eab\u89e3\u6c7a\u65b9\u6848\u81f3\u95dc\u91cd\u8981\u3002\u82e5\u60a8\u5c0d\u65bc\u9999\u6e2fVPS<\/a><\/code>\u6216\u96f2\u4f3a\u670d\u5668<\/a><\/code>\u6709\u8208\u8da3\uff0c\u8acb\u8a2a\u554f\u6211\u5011\u7684\u7db2\u7ad9\u4ee5\u7372\u53d6\u66f4\u591a\u4fe1\u606f\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
\u6df1\u5165\u63a2\u8a0eSQL\u908f\u8f2f\u67e5\u8a62\u7684\u5404\u500b\u968e\u6bb5\uff0c\u4e86\u89e3\u67e5\u8a62\u8655\u7406\u6d41\u7a0b\u3001\u512a\u5316\u6280\u5de7\u53ca\u57f7\u884c\u8a08\u5283\uff0c\u63d0\u5347\u6578\u64da\u64cd\u4f5c\u6548\u7387\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-191838","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/191838","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=191838"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/191838\/revisions"}],"predecessor-version":[{"id":191839,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/191838\/revisions\/191839"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=191838"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=191838"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=191838"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}