{"id":168459,"date":"2024-11-06T12:33:18","date_gmt":"2024-11-06T04:33:18","guid":{"rendered":"https:\/\/server.hk\/cnblog\/168459\/"},"modified":"2024-11-06T12:33:19","modified_gmt":"2024-11-06T04:33:19","slug":"sql-%e8%aa%9e%e5%8f%a5%e5%af%a6%e7%8f%be%e6%95%b8%e6%93%9a%e5%ba%ab%e8%a1%a8%e8%81%af%e6%9f%a5-%e6%95%b8%e6%93%9a%e5%ba%ab%e5%85%a9%e8%a1%a8%e8%81%af%e6%9f%a5","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/168459\/","title":{"rendered":"SQL \u8a9e\u53e5\u5be6\u73fe\u6578\u64da\u5eab\u8868\u806f\u67e5 (\u6578\u64da\u5eab\u5169\u8868\u806f\u67e5)"},"content":{"rendered":"

SQL \u8a9e\u53e5\u5be6\u73fe\u6578\u64da\u5eab\u8868\u806f\u67e5 (\u6578\u64da\u5eab\u5169\u8868\u806f\u67e5)<\/h1>\n

\u5728\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\u4e2d\uff0c\u806f\u67e5\uff08Join\uff09\u662f\u4e00\u7a2e\u975e\u5e38\u91cd\u8981\u7684\u64cd\u4f5c\uff0c\u80fd\u5920\u5c07\u4f86\u81ea\u4e0d\u540c\u8868\u7684\u6578\u64da\u6839\u64da\u67d0\u4e9b\u689d\u4ef6\u9032\u884c\u7d44\u5408\u3002\u9019\u7a2e\u64cd\u4f5c\u5728\u8655\u7406\u95dc\u806f\u6578\u64da\u6642\u5c24\u70ba\u91cd\u8981\uff0c\u56e0\u70ba\u5b83\u80fd\u5920\u5e6b\u52a9\u7528\u6236\u7372\u53d6\u66f4\u5168\u9762\u7684\u4fe1\u606f\u3002\u672c\u6587\u5c07\u6df1\u5165\u63a2\u8a0e SQL \u8a9e\u53e5\u5982\u4f55\u5be6\u73fe\u6578\u64da\u5eab\u8868\u7684\u806f\u67e5\uff0c\u7279\u5225\u662f\u5169\u8868\u806f\u67e5\u7684\u5177\u9ad4\u5be6\u73fe\u65b9\u6cd5\u3002<\/p>\n

\u4ec0\u9ebc\u662f\u806f\u67e5\uff1f<\/h2>\n

\u806f\u67e5\u662f\u6307\u5728 SQL \u67e5\u8a62\u4e2d\uff0c\u6839\u64da\u67d0\u4e9b\u5171\u540c\u7684\u5b57\u6bb5\u5c07\u591a\u500b\u8868\u4e2d\u7684\u6578\u64da\u9032\u884c\u7d44\u5408\u3002\u9019\u6a23\u7684\u64cd\u4f5c\u53ef\u4ee5\u4f7f\u5f97\u7528\u6236\u5728\u67e5\u8a62\u6642\u7372\u5f97\u66f4\u70ba\u8c50\u5bcc\u7684\u6578\u64da\u8996\u5716\u3002\u5e38\u898b\u7684\u806f\u67e5\u985e\u578b\u5305\u62ec\u5167\u806f\u67e5\uff08INNER JOIN\uff09\u3001\u5de6\u806f\u67e5\uff08LEFT JOIN\uff09\u3001\u53f3\u806f\u67e5\uff08RIGHT JOIN\uff09\u548c\u5168\u806f\u67e5\uff08FULL JOIN\uff09\u7b49\u3002<\/p>\n

\u5167\u806f\u67e5\uff08INNER JOIN\uff09<\/h2>\n

\u5167\u806f\u67e5\u662f\u6700\u5e38\u7528\u7684\u806f\u67e5\u65b9\u5f0f\uff0c\u5b83\u53ea\u8fd4\u56de\u5728\u5169\u500b\u8868\u4e2d\u90fd\u5b58\u5728\u7684\u8a18\u9304\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u7c21\u55ae\u7684\u4f8b\u5b50\uff0c\u5047\u8a2d\u6211\u5011\u6709\u5169\u500b\u8868\uff1acustomers<\/code>\uff08\u5ba2\u6236\u8868\uff09\u548c orders<\/code>\uff08\u8a02\u55ae\u8868\uff09\u3002<\/p>\n

CREATE TABLE customers (\n    customer_id INT PRIMARY KEY,\n    customer_name VARCHAR(100)\n);\n\nCREATE TABLE orders (\n    order_id INT PRIMARY KEY,\n    customer_id INT,\n    order_date DATE,\n    FOREIGN KEY (customer_id) REFERENCES customers(customer_id)\n);\n<\/code><\/pre>\n
\u5982\u679c\u6211\u5011\u60f3\u8981\u67e5\u8a62\u6240\u6709\u5ba2\u6236\u53ca\u5176\u8a02\u55ae\u7684\u8a73\u7d30\u4fe1\u606f\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b SQL \u8a9e\u53e5\uff1a<\/p>\n
SELECT customers.customer_name, orders.order_date\nFROM customers\nINNER JOIN orders ON customers.customer_id = orders.customer_id;\n<\/code><\/pre>\n
\u9019\u689d\u67e5\u8a62\u5c07\u8fd4\u56de\u6240\u6709\u6709\u8a02\u55ae\u7684\u5ba2\u6236\u53ca\u5176\u8a02\u55ae\u65e5\u671f\u3002<\/p>\n
\u5de6\u806f\u67e5\uff08LEFT JOIN\uff09<\/h2>\n
\u5de6\u806f\u67e5\u6703\u8fd4\u56de\u5de6\u8868\u4e2d\u7684\u6240\u6709\u8a18\u9304\uff0c\u5373\u4f7f\u53f3\u8868\u4e2d\u6c92\u6709\u5339\u914d\u7684\u8a18\u9304\u3002\u9019\u5c0d\u65bc\u9700\u8981\u986f\u793a\u6240\u6709\u5ba2\u6236\u7684\u60c5\u6cc1\u975e\u5e38\u6709\u7528\uff0c\u5373\u4f7f\u67d0\u4e9b\u5ba2\u6236\u6c92\u6709\u4e0b\u8a02\u55ae\u3002<\/p>\n
SELECT customers.customer_name, orders.order_date\nFROM customers\nLEFT JOIN orders ON customers.customer_id = orders.customer_id;\n<\/code><\/pre>\n
\u9019\u689d\u67e5\u8a62\u5c07\u8fd4\u56de\u6240\u6709\u5ba2\u6236\u7684\u540d\u7a31\u53ca\u5176\u8a02\u55ae\u65e5\u671f\uff0c\u5982\u679c\u67d0\u500b\u5ba2\u6236\u6c92\u6709\u8a02\u55ae\uff0c\u5247\u8a02\u55ae\u65e5\u671f\u5c07\u986f\u793a\u70ba NULL<\/code>\u3002<\/p>\n
\u53f3\u806f\u67e5\uff08RIGHT JOIN\uff09<\/h2>\n
\u53f3\u806f\u67e5\u8207\u5de6\u806f\u67e5\u76f8\u53cd\uff0c\u5b83\u8fd4\u56de\u53f3\u8868\u4e2d\u7684\u6240\u6709\u8a18\u9304\uff0c\u5373\u4f7f\u5de6\u8868\u4e2d\u6c92\u6709\u5339\u914d\u7684\u8a18\u9304\u3002\u9019\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\u4e5f\u975e\u5e38\u6709\u7528\u3002<\/p>\n
SELECT customers.customer_name, orders.order_date\nFROM customers\nRIGHT JOIN orders ON customers.customer_id = orders.customer_id;\n<\/code><\/pre>\n
\u9019\u689d\u67e5\u8a62\u5c07\u8fd4\u56de\u6240\u6709\u8a02\u55ae\u7684\u65e5\u671f\u53ca\u5176\u5c0d\u61c9\u7684\u5ba2\u6236\u540d\u7a31\uff0c\u5982\u679c\u67d0\u500b\u8a02\u55ae\u6c92\u6709\u5c0d\u61c9\u7684\u5ba2\u6236\uff0c\u5247\u5ba2\u6236\u540d\u7a31\u5c07\u986f\u793a\u70ba NULL<\/code>\u3002<\/p>\n
\u5168\u806f\u67e5\uff08FULL JOIN\uff09<\/h2>\n
\u5168\u806f\u67e5\u6703\u8fd4\u56de\u5169\u500b\u8868\u4e2d\u7684\u6240\u6709\u8a18\u9304\uff0c\u7121\u8ad6\u662f\u5426\u6709\u5339\u914d\u7684\u8a18\u9304\u3002\u9019\u5728\u9700\u8981\u7372\u53d6\u6240\u6709\u6578\u64da\u7684\u60c5\u6cc1\u4e0b\u975e\u5e38\u6709\u7528\u3002<\/p>\n
SELECT customers.customer_name, orders.order_date\nFROM customers\nFULL JOIN orders ON customers.customer_id = orders.customer_id;\n<\/code><\/pre>\n
\u9019\u689d\u67e5\u8a62\u5c07\u8fd4\u56de\u6240\u6709\u5ba2\u6236\u548c\u6240\u6709\u8a02\u55ae\u7684\u8a73\u7d30\u4fe1\u606f\uff0c\u5c0d\u65bc\u6c92\u6709\u5339\u914d\u7684\u8a18\u9304\uff0c\u5c07\u986f\u793a\u70ba NULL<\/code>\u3002<\/p>\n
\u7d50\u8ad6<\/h2>\n
\u901a\u904e\u4f7f\u7528 SQL \u7684\u806f\u67e5\u529f\u80fd\uff0c\u958b\u767c\u8005\u53ef\u4ee5\u9748\u6d3b\u5730\u5f9e\u591a\u500b\u8868\u4e2d\u63d0\u53d6\u548c\u7d44\u5408\u6578\u64da\uff0c\u5f9e\u800c\u7372\u5f97\u66f4\u5168\u9762\u7684\u6578\u64da\u8996\u5716\u3002\u7121\u8ad6\u662f\u5167\u806f\u67e5\u3001\u5de6\u806f\u67e5\u3001\u53f3\u806f\u67e5\u9084\u662f\u5168\u806f\u67e5\uff0c\u9019\u4e9b\u6280\u8853\u90fd\u80fd\u5920\u5e6b\u52a9\u7528\u6236\u66f4\u6709\u6548\u5730\u9032\u884c\u6578\u64da\u5206\u6790\u548c\u5831\u544a\u3002<\/p>\n
\u5982\u679c\u60a8\u6b63\u5728\u5c0b\u627e\u9ad8\u6548\u7684\u6578\u64da\u5eab\u89e3\u6c7a\u65b9\u6848\uff0c\u8003\u616e\u4f7f\u7528 \u9999\u6e2fVPS<\/a> \u4f86\u642d\u5efa\u60a8\u7684\u6578\u64da\u5eab\u74b0\u5883\uff0c\u4eab\u53d7\u7a69\u5b9a\u548c\u9ad8\u6548\u7684\u670d\u52d9\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
\u5b78\u7fd2\u5982\u4f55\u4f7f\u7528 SQL \u8a9e\u53e5\u5be6\u73fe\u6578\u64da\u5eab\u8868\u806f\u67e5\uff0c\u638c\u63e1\u5169\u8868\u806f\u67e5\u7684\u6280\u5de7\uff0c\u63d0\u5347\u6578\u64da\u67e5\u8a62\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-168459","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/168459","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=168459"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/168459\/revisions"}],"predecessor-version":[{"id":168460,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/168459\/revisions\/168460"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=168459"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=168459"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=168459"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}