{"id":168369,"date":"2024-11-06T11:48:18","date_gmt":"2024-11-06T03:48:18","guid":{"rendered":"https:\/\/server.hk\/cnblog\/168369\/"},"modified":"2024-11-06T11:48:19","modified_gmt":"2024-11-06T03:48:19","slug":"sql-%e6%95%b8%e6%93%9a%e5%ba%ab%e4%b8%ad%e7%9a%84%e7%ad%89%e5%80%bc%e9%80%a3%e6%8e%a5%e6%98%af%e5%a6%82%e4%bd%95%e5%af%a6%e7%8f%be%e7%9a%84%ef%bc%9f-sql-%e6%95%b8%e6%93%9a%e5%ba%ab-%e7%ad%89%e5%80%bc","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/168369\/","title":{"rendered":"SQL \u6578\u64da\u5eab\u4e2d\u7684\u7b49\u503c\u9023\u63a5\u662f\u5982\u4f55\u5be6\u73fe\u7684\uff1f (sql \u6578\u64da\u5eab \u7b49\u503c\u9023\u63a5)"},"content":{"rendered":"<h1 id=\"sql-%e6%95%b8%e6%93%9a%e5%ba%ab%e4%b8%ad%e7%9a%84%e7%ad%89%e5%80%bc%e9%80%a3%e6%8e%a5%e6%98%af%e5%a6%82%e4%bd%95%e5%af%a6%e7%8f%be%e7%9a%84%ef%bc%9f-fHxMTBRQMZ\">SQL \u6578\u64da\u5eab\u4e2d\u7684\u7b49\u503c\u9023\u63a5\u662f\u5982\u4f55\u5be6\u73fe\u7684\uff1f<\/h1>\n<p>\u5728\u95dc\u65bc\u6578\u64da\u5eab\u7684\u64cd\u4f5c\u4e2d\uff0c\u7b49\u503c\u9023\u63a5\uff08Equi Join\uff09\u662f\u4e00\u7a2e\u5e38\u898b\u4e14\u91cd\u8981\u7684\u6280\u8853\u3002\u5b83\u5141\u8a31\u6211\u5011\u5f9e\u591a\u500b\u8868\u4e2d\u63d0\u53d6\u76f8\u95dc\u6578\u64da\uff0c\u4e26\u4e14\u5728\u8a31\u591a\u5be6\u969b\u61c9\u7528\u4e2d\u90fd\u626e\u6f14\u8457\u95dc\u9375\u89d2\u8272\u3002\u672c\u6587\u5c07\u6df1\u5165\u63a2\u8a0e\u7b49\u503c\u9023\u63a5\u7684\u6982\u5ff5\u3001\u5be6\u73fe\u65b9\u5f0f\u4ee5\u53ca\u5176\u5728 SQL \u6578\u64da\u5eab\u4e2d\u7684\u61c9\u7528\u3002<\/p>\n<h2 id=\"%e4%bb%80%e9%ba%bc%e6%98%af%e7%ad%89%e5%80%bc%e9%80%a3%e6%8e%a5%ef%bc%9f-fHxMTBRQMZ\">\u4ec0\u9ebc\u662f\u7b49\u503c\u9023\u63a5\uff1f<\/h2>\n<p>\u7b49\u503c\u9023\u63a5\u662f\u4e00\u7a2e\u57fa\u65bc\u76f8\u7b49\u689d\u4ef6\u7684\u9023\u63a5\u64cd\u4f5c\uff0c\u901a\u5e38\u7528\u65bc\u5f9e\u5169\u500b\u6216\u591a\u500b\u8868\u4e2d\u9078\u53d6\u6578\u64da\u3002\u9019\u7a2e\u9023\u63a5\u7684\u57fa\u672c\u539f\u5247\u662f\u901a\u904e\u6bd4\u8f03\u4e00\u500b\u8868\u4e2d\u7684\u67d0\u500b\u5b57\u6bb5\u8207\u53e6\u4e00\u500b\u8868\u4e2d\u7684\u76f8\u61c9\u5b57\u6bb5\u4f86\u9032\u884c\u6578\u64da\u7684\u5339\u914d\u3002\u7576\u9019\u4e9b\u5b57\u6bb5\u7684\u503c\u76f8\u7b49\u6642\uff0c\u7cfb\u7d71\u5c07\u8fd4\u56de\u9019\u4e9b\u884c\u7684\u7d44\u5408\u3002<\/p>\n<h2 id=\"%e7%ad%89%e5%80%bc%e9%80%a3%e6%8e%a5%e7%9a%84%e5%9f%ba%e6%9c%ac%e8%aa%9e%e6%b3%95-fHxMTBRQMZ\">\u7b49\u503c\u9023\u63a5\u7684\u57fa\u672c\u8a9e\u6cd5<\/h2>\n<p>\u5728 SQL \u4e2d\uff0c\u7b49\u503c\u9023\u63a5\u901a\u5e38\u4f7f\u7528 <code>JOIN<\/code> \u95dc\u9375\u5b57\u4f86\u5be6\u73fe\u3002\u4ee5\u4e0b\u662f\u7b49\u503c\u9023\u63a5\u7684\u57fa\u672c\u8a9e\u6cd5\uff1a<\/p>\n<pre><code>\nSELECT \u88681.\u5b57\u6bb51, \u88682.\u5b57\u6bb52\nFROM \u88681\nJOIN \u88682 ON \u88681.\u5b57\u6bb5 = \u88682.\u5b57\u6bb5;\n<\/code><\/pre>\n<p>\u5728\u9019\u6bb5\u4ee3\u78bc\u4e2d\uff0c<code>\u88681<\/code> \u548c <code>\u88682<\/code> \u662f\u6211\u5011\u8981\u9023\u63a5\u7684\u5169\u500b\u8868\uff0c\u800c <code>\u5b57\u6bb5<\/code> \u5247\u662f\u7528\u65bc\u6bd4\u8f03\u7684\u5217\u3002\u7576\u9019\u4e9b\u5217\u7684\u503c\u76f8\u7b49\u6642\uff0c\u5c07\u8fd4\u56de\u76f8\u61c9\u7684\u6578\u64da\u3002<\/p>\n<h2 id=\"%e7%ad%89%e5%80%bc%e9%80%a3%e6%8e%a5%e7%9a%84%e7%a4%ba%e4%be%8b-fHxMTBRQMZ\">\u7b49\u503c\u9023\u63a5\u7684\u793a\u4f8b<\/h2>\n<p>\u5047\u8a2d\u6211\u5011\u6709\u5169\u500b\u8868\uff1a<code>Customers<\/code>\uff08\u5ba2\u6236\uff09\u548c <code>Orders<\/code>\uff08\u8a02\u55ae\uff09\u3002<code>Customers<\/code> \u8868\u4e2d\u5305\u542b\u5ba2\u6236\u7684\u57fa\u672c\u4fe1\u606f\uff0c\u800c <code>Orders<\/code> \u8868\u4e2d\u5247\u5305\u542b\u6bcf\u500b\u5ba2\u6236\u7684\u8a02\u55ae\u4fe1\u606f\u3002\u9019\u5169\u500b\u8868\u901a\u904e <code>CustomerID<\/code> \u9032\u884c\u95dc\u806f\u3002<\/p>\n<pre><code>\nSELECT Customers.CustomerName, Orders.OrderID\nFROM Customers\nJOIN Orders ON Customers.CustomerID = Orders.CustomerID;\n<\/code><\/pre>\n<p>\u5728\u9019\u500b\u67e5\u8a62\u4e2d\uff0c\u6211\u5011\u9078\u64c7\u4e86\u5ba2\u6236\u540d\u7a31\u548c\u8a02\u55ae ID\uff0c\u4e26\u901a\u904e <code>CustomerID<\/code> \u9032\u884c\u4e86\u7b49\u503c\u9023\u63a5\u3002\u9019\u6a23\uff0c\u6211\u5011\u5c31\u80fd\u5920\u7372\u5f97\u6bcf\u4f4d\u5ba2\u6236\u53ca\u5176\u76f8\u61c9\u8a02\u55ae\u7684\u5217\u8868\u3002<\/p>\n<h2 id=\"%e7%ad%89%e5%80%bc%e9%80%a3%e6%8e%a5%e7%9a%84%e9%a1%9e%e5%9e%8b-fHxMTBRQMZ\">\u7b49\u503c\u9023\u63a5\u7684\u985e\u578b<\/h2>\n<p>\u7b49\u503c\u9023\u63a5\u53ef\u4ee5\u5206\u70ba\u5e7e\u7a2e\u985e\u578b\uff0c\u5305\u62ec\uff1a<\/p>\n<ul>\n<li><strong>\u5167\u90e8\u9023\u63a5\uff08Inner Join\uff09<\/strong>\uff1a\u53ea\u8fd4\u56de\u5169\u500b\u8868\u4e2d\u5339\u914d\u7684\u884c\u3002<\/li>\n<li><strong>\u5916\u90e8\u9023\u63a5\uff08Outer Join\uff09<\/strong>\uff1a\u5305\u62ec\u4e0d\u5339\u914d\u7684\u884c\uff0c\u5206\u70ba\u5de6\u5916\u9023\u63a5\uff08Left Outer Join\uff09\u548c\u53f3\u5916\u9023\u63a5\uff08Right Outer Join\uff09\u3002<\/li>\n<li><strong>\u4ea4\u53c9\u9023\u63a5\uff08Cross Join\uff09<\/strong>\uff1a\u8fd4\u56de\u5169\u500b\u8868\u7684\u7b1b\u5361\u723e\u7a4d\uff0c\u5373\u6bcf\u500b\u8868\u7684\u6bcf\u4e00\u884c\u90fd\u8207\u53e6\u4e00\u500b\u8868\u7684\u6bcf\u4e00\u884c\u76f8\u9023\u63a5\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%ad%89%e5%80%bc%e9%80%a3%e6%8e%a5%e7%9a%84%e6%80%a7%e8%83%bd%e8%80%83%e9%87%8f-fHxMTBRQMZ\">\u7b49\u503c\u9023\u63a5\u7684\u6027\u80fd\u8003\u91cf<\/h2>\n<p>\u5728\u4f7f\u7528\u7b49\u503c\u9023\u63a5\u6642\uff0c\u6027\u80fd\u662f\u4e00\u500b\u91cd\u8981\u7684\u8003\u91cf\u56e0\u7d20\u3002\u7576\u6578\u64da\u8868\u7684\u5927\u5c0f\u589e\u9577\u6642\uff0c\u67e5\u8a62\u7684\u6548\u7387\u53ef\u80fd\u6703\u53d7\u5230\u5f71\u97ff\u3002\u70ba\u4e86\u63d0\u9ad8\u6027\u80fd\uff0c\u53ef\u4ee5\u8003\u616e\u4ee5\u4e0b\u5e7e\u9ede\uff1a<\/p>\n<ul>\n<li>\u78ba\u4fdd\u5728\u9023\u63a5\u7684\u5b57\u6bb5\u4e0a\u5efa\u7acb\u7d22\u5f15\uff0c\u4ee5\u52a0\u5feb\u67e5\u8a62\u901f\u5ea6\u3002<\/li>\n<li>\u907f\u514d\u5728\u9023\u63a5\u4e2d\u4f7f\u7528\u904e\u591a\u7684\u8868\uff0c\u9019\u6a23\u53ef\u4ee5\u6e1b\u5c11\u8a08\u7b97\u7684\u8907\u96dc\u6027\u3002<\/li>\n<li>\u4f7f\u7528\u9069\u7576\u7684\u67e5\u8a62\u8a08\u5283\uff0c\u78ba\u4fdd\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\u80fd\u5920\u6709\u6548\u5730\u57f7\u884c\u67e5\u8a62\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b8%bd%e7%b5%90-fHxMTBRQMZ\">\u7e3d\u7d50<\/h2>\n<p>\u7b49\u503c\u9023\u63a5\u662f SQL \u6578\u64da\u5eab\u4e2d\u4e00\u7a2e\u5f37\u5927\u4e14\u9748\u6d3b\u7684\u6578\u64da\u63d0\u53d6\u6280\u8853\u3002\u901a\u904e\u7406\u89e3\u5176\u57fa\u672c\u6982\u5ff5\u548c\u5be6\u73fe\u65b9\u5f0f\uff0c\u958b\u767c\u8005\u53ef\u4ee5\u66f4\u6709\u6548\u5730\u5f9e\u591a\u500b\u8868\u4e2d\u7372\u53d6\u6240\u9700\u7684\u6578\u64da\u3002\u7121\u8ad6\u662f\u5728\u65e5\u5e38\u7684\u6578\u64da\u67e5\u8a62\u9084\u662f\u8907\u96dc\u7684\u6578\u64da\u5206\u6790\u4e2d\uff0c\u7b49\u503c\u9023\u63a5\u90fd\u80fd\u63d0\u4f9b\u91cd\u8981\u7684\u652f\u6301\u3002<\/p>\n<p>\u5982\u679c\u60a8\u6b63\u5728\u5c0b\u627e\u9ad8\u6548\u7684 <a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a> \u89e3\u6c7a\u65b9\u6848\uff0cServer.HK \u63d0\u4f9b\u591a\u7a2e\u9078\u64c7\uff0c\u6eff\u8db3\u60a8\u7684\u9700\u6c42\u3002\u7121\u8ad6\u662f\u6578\u64da\u5eab\u7ba1\u7406\u9084\u662f\u7db2\u7ad9\u6258\u7ba1\uff0c\u6211\u5011\u7684 <a href=\"https:\/\/server.hk\">\u4e91\u670d\u52d9\u5668<\/a> \u90fd\u80fd\u70ba\u60a8\u63d0\u4f9b\u7a69\u5b9a\u7684\u652f\u6301\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4e86\u89e3SQL\u6578\u64da\u5eab\u4e2d\u7b49\u503c\u9023\u63a5\u7684\u5be6\u73fe\u65b9\u5f0f\uff0c\u63a2\u7d22\u5982\u4f55\u901a\u904eJOIN\u8a9e\u53e5\u6709\u6548\u5730\u67e5\u8a62\u548c\u6574\u5408\u6578\u64da\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-168369","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/168369","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=168369"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/168369\/revisions"}],"predecessor-version":[{"id":168370,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/168369\/revisions\/168370"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=168369"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=168369"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=168369"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}