{"id":168397,"date":"2024-11-06T12:02:22","date_gmt":"2024-11-06T04:02:22","guid":{"rendered":"https:\/\/server.hk\/cnblog\/168397\/"},"modified":"2024-11-06T12:02:23","modified_gmt":"2024-11-06T04:02:23","slug":"sql-%e5%a4%96%e9%80%a3%e6%8e%a5%e7%b0%a1%e4%bb%8b","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/168397\/","title":{"rendered":"SQL \u5916\u9023\u63a5\u7c21\u4ecb"},"content":{"rendered":"

SQL \u5916\u9023\u63a5\u7c21\u4ecb<\/h1>\n

\u5728\u8cc7\u6599\u5eab\u7ba1\u7406\u7cfb\u7d71\u4e2d\uff0cSQL\uff08\u7d50\u69cb\u5316\u67e5\u8a62\u8a9e\u8a00\uff09\u662f\u4e00\u7a2e\u7528\u65bc\u67e5\u8a62\u548c\u64cd\u4f5c\u8cc7\u6599\u7684\u6a19\u6e96\u8a9e\u8a00\u3002\u7576\u6211\u5011\u9700\u8981\u5f9e\u591a\u500b\u8cc7\u6599\u8868\u4e2d\u63d0\u53d6\u8cc7\u6599\u6642\uff0c\u5916\u9023\u63a5\uff08Outer Join\uff09\u662f\u4e00\u500b\u975e\u5e38\u91cd\u8981\u7684\u6982\u5ff5\u3002\u672c\u6587\u5c07\u4ecb\u7d39\u5916\u9023\u63a5\u7684\u57fa\u672c\u6982\u5ff5\u3001\u985e\u578b\u53ca\u5176\u4f7f\u7528\u7bc4\u4f8b\u3002<\/p>\n

\u5916\u9023\u63a5\u7684\u5b9a\u7fa9<\/h2>\n

\u5916\u9023\u63a5\u662f\u4e00\u7a2e\u9023\u63a5\u64cd\u4f5c\uff0c\u5141\u8a31\u5f9e\u5169\u500b\u6216\u591a\u500b\u8cc7\u6599\u8868\u4e2d\u6aa2\u7d22\u8cc7\u6599\uff0c\u5373\u4f7f\u5728\u67d0\u4e9b\u8cc7\u6599\u8868\u4e2d\u6c92\u6709\u5339\u914d\u7684\u884c\u3002\u9019\u610f\u5473\u8457\u5916\u9023\u63a5\u6703\u8fd4\u56de\u6240\u6709\u884c\uff0c\u5373\u4f7f\u67d0\u4e9b\u884c\u5728\u9023\u63a5\u7684\u8cc7\u6599\u8868\u4e2d\u6c92\u6709\u5c0d\u61c9\u7684\u8cc7\u6599\u3002\u5916\u9023\u63a5\u4e3b\u8981\u5206\u70ba\u4e09\u7a2e\u985e\u578b\uff1a\u5de6\u5916\u9023\u63a5\uff08Left Outer Join\uff09\u3001\u53f3\u5916\u9023\u63a5\uff08Right Outer Join\uff09\u548c\u5168\u5916\u9023\u63a5\uff08Full Outer Join\uff09\u3002<\/p>\n

\u5916\u9023\u63a5\u7684\u985e\u578b<\/h2>\n

1. \u5de6\u5916\u9023\u63a5\uff08Left Outer Join\uff09<\/h3>\n

\u5de6\u5916\u9023\u63a5\u6703\u8fd4\u56de\u5de6\u5074\u8cc7\u6599\u8868\u4e2d\u7684\u6240\u6709\u884c\uff0c\u4ee5\u53ca\u53f3\u5074\u8cc7\u6599\u8868\u4e2d\u5339\u914d\u7684\u884c\u3002\u5982\u679c\u53f3\u5074\u8cc7\u6599\u8868\u4e2d\u6c92\u6709\u5339\u914d\u7684\u884c\uff0c\u5247\u7d50\u679c\u4e2d\u6703\u986f\u793a\u5de6\u5074\u8cc7\u6599\u8868\u7684\u884c\uff0c\u4e26\u4e14\u53f3\u5074\u8cc7\u6599\u8868\u7684\u6b04\u4f4d\u5c07\u986f\u793a\u70baNULL\u3002<\/p>\n

SELECT A.*, B.*\nFROM TableA A\nLEFT OUTER JOIN TableB B ON A.id = B.a_id;<\/code><\/pre>\n
2. \u53f3\u5916\u9023\u63a5\uff08Right Outer Join\uff09<\/h3>\n
\u53f3\u5916\u9023\u63a5\u8207\u5de6\u5916\u9023\u63a5\u76f8\u53cd\uff0c\u5b83\u6703\u8fd4\u56de\u53f3\u5074\u8cc7\u6599\u8868\u4e2d\u7684\u6240\u6709\u884c\uff0c\u4ee5\u53ca\u5de6\u5074\u8cc7\u6599\u8868\u4e2d\u5339\u914d\u7684\u884c\u3002\u5982\u679c\u5de6\u5074\u8cc7\u6599\u8868\u4e2d\u6c92\u6709\u5339\u914d\u7684\u884c\uff0c\u5247\u7d50\u679c\u4e2d\u6703\u986f\u793a\u53f3\u5074\u8cc7\u6599\u8868\u7684\u884c\uff0c\u4e26\u4e14\u5de6\u5074\u8cc7\u6599\u8868\u7684\u6b04\u4f4d\u5c07\u986f\u793a\u70baNULL\u3002<\/p>\n
SELECT A.*, B.*\nFROM TableA A\nRIGHT OUTER JOIN TableB B ON A.id = B.a_id;<\/code><\/pre>\n
3. \u5168\u5916\u9023\u63a5\uff08Full Outer Join\uff09<\/h3>\n
\u5168\u5916\u9023\u63a5\u6703\u8fd4\u56de\u5169\u500b\u8cc7\u6599\u8868\u4e2d\u7684\u6240\u6709\u884c\u3002\u5982\u679c\u67d0\u4e00\u5074\u7684\u8cc7\u6599\u8868\u4e2d\u6c92\u6709\u5339\u914d\u7684\u884c\uff0c\u5247\u8a72\u5074\u7684\u6b04\u4f4d\u5c07\u986f\u793a\u70baNULL\u3002\u9019\u7a2e\u9023\u63a5\u65b9\u5f0f\u975e\u5e38\u9069\u5408\u9700\u8981\u5f9e\u5169\u500b\u8cc7\u6599\u8868\u4e2d\u7372\u53d6\u6240\u6709\u8cc7\u6599\u7684\u60c5\u6cc1\u3002<\/p>\n
SELECT A.*, B.*\nFROM TableA A\nFULL OUTER JOIN TableB B ON A.id = B.a_id;<\/code><\/pre>\n
\u5916\u9023\u63a5\u7684\u61c9\u7528\u5834\u666f<\/h2>\n
\u5916\u9023\u63a5\u5728\u8a31\u591a\u5be6\u969b\u61c9\u7528\u4e2d\u90fd\u975e\u5e38\u6709\u7528\u3002\u4f8b\u5982\uff0c\u5728\u4e00\u500b\u96fb\u5b50\u5546\u52d9\u7cfb\u7d71\u4e2d\uff0c\u60a8\u53ef\u80fd\u9700\u8981\u5f9e\u9867\u5ba2\u8cc7\u6599\u8868\u548c\u8a02\u55ae\u8cc7\u6599\u8868\u4e2d\u7372\u53d6\u8cc7\u6599\u3002\u4f7f\u7528\u5de6\u5916\u9023\u63a5\u53ef\u4ee5\u5e6b\u52a9\u60a8\u7372\u53d6\u6240\u6709\u9867\u5ba2\u7684\u8cc7\u6599\uff0c\u5373\u4f7f\u67d0\u4e9b\u9867\u5ba2\u5c1a\u672a\u4e0b\u8a02\u55ae\u3002\u5728\u9019\u7a2e\u60c5\u6cc1\u4e0b\uff0c\u60a8\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u67e5\u8a62\uff1a<\/p>\n
SELECT Customers.name, Orders.order_id\nFROM Customers\nLEFT OUTER JOIN Orders ON Customers.id = Orders.customer_id;<\/code><\/pre>\n
\u9019\u6a23\u7684\u67e5\u8a62\u5c07\u8fd4\u56de\u6240\u6709\u9867\u5ba2\u7684\u59d3\u540d\u548c\u4ed6\u5011\u7684\u8a02\u55aeID\uff0c\u5c0d\u65bc\u5c1a\u672a\u4e0b\u8a02\u55ae\u7684\u9867\u5ba2\uff0c\u8a02\u55aeID\u5c07\u986f\u793a\u70baNULL\u3002<\/p>\n
\u7e3d\u7d50<\/h2>\n
\u5916\u9023\u63a5\u662f\u4e00\u7a2e\u5f37\u5927\u7684\u5de5\u5177\uff0c\u80fd\u5920\u5e6b\u52a9\u958b\u767c\u8005\u5f9e\u591a\u500b\u8cc7\u6599\u8868\u4e2d\u63d0\u53d6\u6240\u9700\u7684\u8cc7\u6599\u3002\u7121\u8ad6\u662f\u5de6\u5916\u9023\u63a5\u3001\u53f3\u5916\u9023\u63a5\u9084\u662f\u5168\u5916\u9023\u63a5\uff0c\u9019\u4e9b\u6280\u8853\u90fd\u80fd\u5920\u5728\u4e0d\u540c\u7684\u60c5\u5883\u4e0b\u63d0\u4f9b\u9748\u6d3b\u7684\u89e3\u6c7a\u65b9\u6848\u3002\u5c0d\u65bc\u9700\u8981\u8655\u7406\u8907\u96dc\u8cc7\u6599\u95dc\u4fc2\u7684\u61c9\u7528\uff0c\u638c\u63e1\u5916\u9023\u63a5\u7684\u4f7f\u7528\u662f\u975e\u5e38\u91cd\u8981\u7684\u3002<\/p>\n
\u5982\u679c\u60a8\u6b63\u5728\u5c0b\u627e\u9ad8\u6548\u7684 \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 \u4e91\u4f3a\u670d\u5668<\/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 SQL \u5916\u9023\u63a5\u7684\u57fa\u672c\u6982\u5ff5\uff0c\u5b78\u7fd2\u5982\u4f55\u4f7f\u7528\u5916\u9023\u63a5\u67e5\u8a62\u591a\u500b\u8868\u683c\u4e2d\u7684\u6578\u64da\uff0c\u63d0\u5347\u6578\u64da\u5206\u6790\u80fd\u529b\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-168397","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/168397","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=168397"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/168397\/revisions"}],"predecessor-version":[{"id":168398,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/168397\/revisions\/168398"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=168397"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=168397"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=168397"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}