{"id":75270,"date":"2024-10-15T23:25:30","date_gmt":"2024-10-15T15:25:30","guid":{"rendered":"https:\/\/server.hk\/cnblog\/75270\/"},"modified":"2024-10-15T23:25:30","modified_gmt":"2024-10-15T15:25:30","slug":"mysql-%e5%a4%9a%e8%a1%a8%e8%81%af%e5%90%88%e6%9f%a5%e8%a9%a2%e6%9c%89%e4%bd%95%e8%ac%9b%e7%a9%b6%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/75270\/","title":{"rendered":"MySQL \u591a\u8868\u806f\u5408\u67e5\u8a62\u6709\u4f55\u8b1b\u7a76\uff1f"},"content":{"rendered":"<h1 id=\"mysql-%e5%a4%9a%e8%a1%a8%e8%81%af%e5%90%88%e6%9f%a5%e8%a9%a2%e6%9c%89%e4%bd%95%e8%ac%9b%e7%a9%b6%ef%bc%9f-jXVEIsNrqb\">MySQL \u591a\u8868\u806f\u5408\u67e5\u8a62\u6709\u4f55\u8b1b\u7a76\uff1f<\/h1>\n<p>\u5728\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\u4e2d\uff0cMySQL \u662f\u4e00\u500b\u5ee3\u6cdb\u4f7f\u7528\u7684\u958b\u6e90\u95dc\u806f\u6578\u64da\u5eab\u3002\u7576\u6d89\u53ca\u5230\u591a\u8868\u806f\u5408\u67e5\u8a62\u6642\uff0c\u9019\u662f\u4e00\u500b\u5f37\u5927\u7684\u529f\u80fd\uff0c\u53ef\u4ee5\u8b93\u7528\u6236\u5f9e\u591a\u500b\u8868\u4e2d\u63d0\u53d6\u548c\u6574\u5408\u6578\u64da\u3002\u672c\u6587\u5c07\u63a2\u8a0e MySQL \u591a\u8868\u806f\u5408\u67e5\u8a62\u7684\u57fa\u672c\u6982\u5ff5\u3001\u4f7f\u7528\u65b9\u6cd5\u53ca\u5176\u6ce8\u610f\u4e8b\u9805\u3002<\/p>\n<h2 id=\"%e4%bb%80%e9%ba%bc%e6%98%af%e5%a4%9a%e8%a1%a8%e8%81%af%e5%90%88%e6%9f%a5%e8%a9%a2%ef%bc%9f-jXVEIsNrqb\">\u4ec0\u9ebc\u662f\u591a\u8868\u806f\u5408\u67e5\u8a62\uff1f<\/h2>\n<p>\u591a\u8868\u806f\u5408\u67e5\u8a62\u662f\u6307\u5728\u4e00\u500b SQL \u67e5\u8a62\u4e2d\u540c\u6642\u67e5\u8a62\u591a\u500b\u8868\u7684\u6578\u64da\u3002\u9019\u901a\u5e38\u662f\u901a\u904e\u4f7f\u7528 JOIN \u8a9e\u53e5\u4f86\u5be6\u73fe\u7684\u3002JOIN \u53ef\u4ee5\u6839\u64da\u8868\u4e4b\u9593\u7684\u95dc\u806f\u689d\u4ef6\uff0c\u5c07\u4f86\u81ea\u4e0d\u540c\u8868\u7684\u6578\u64da\u7d50\u5408\u5728\u4e00\u8d77\u3002<\/p>\n<h2 id=\"join-%e7%9a%84%e9%a1%9e%e5%9e%8b-jXVEIsNrqb\">JOIN \u7684\u985e\u578b<\/h2>\n<p>\u5728 MySQL \u4e2d\uff0c\u4e3b\u8981\u6709\u5e7e\u7a2e JOIN \u985e\u578b\uff1a<\/p>\n<ul>\n<li><strong>INNER JOIN<\/strong>: \u53ea\u8fd4\u56de\u5169\u500b\u8868\u4e2d\u5339\u914d\u7684\u884c\u3002<\/li>\n<li><strong>LEFT JOIN<\/strong>: \u8fd4\u56de\u5de6\u8868\u7684\u6240\u6709\u884c\uff0c\u5373\u4f7f\u53f3\u8868\u4e2d\u6c92\u6709\u5339\u914d\u7684\u884c\u3002<\/li>\n<li><strong>RIGHT JOIN<\/strong>: \u8fd4\u56de\u53f3\u8868\u7684\u6240\u6709\u884c\uff0c\u5373\u4f7f\u5de6\u8868\u4e2d\u6c92\u6709\u5339\u914d\u7684\u884c\u3002<\/li>\n<li><strong>FULL OUTER JOIN<\/strong>: \u8fd4\u56de\u5169\u500b\u8868\u4e2d\u7684\u6240\u6709\u884c\uff0c\u7121\u8ad6\u662f\u5426\u6709\u5339\u914d\u3002<\/li>\n<\/ul>\n<h2 id=\"%e5%9f%ba%e6%9c%ac%e8%aa%9e%e6%b3%95-jXVEIsNrqb\">\u57fa\u672c\u8a9e\u6cd5<\/h2>\n<p>\u4ee5\u4e0b\u662f\u4f7f\u7528 INNER JOIN \u7684\u57fa\u672c\u8a9e\u6cd5\uff1a<\/p>\n<pre><code>SELECT \u5217\u540d\nFROM \u88681\nINNER JOIN \u88682\nON \u88681.\u5217\u540d = \u88682.\u5217\u540d;<\/code><\/pre>\n<p>\u4f8b\u5982\uff0c\u5047\u8a2d\u6709\u5169\u500b\u8868\uff1a<code>customers<\/code> \u548c <code>orders<\/code>\uff0c\u6211\u5011\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u67e5\u8a62\u4f86\u7372\u53d6\u6240\u6709\u5ba2\u6236\u53ca\u5176\u8a02\u55ae\uff1a<\/p>\n<pre><code>SELECT customers.name, orders.order_id\nFROM customers\nINNER JOIN orders\nON customers.id = orders.customer_id;<\/code><\/pre>\n<h2 id=\"%e6%b3%a8%e6%84%8f%e4%ba%8b%e9%a0%85-jXVEIsNrqb\">\u6ce8\u610f\u4e8b\u9805<\/h2>\n<p>\u5728\u9032\u884c\u591a\u8868\u806f\u5408\u67e5\u8a62\u6642\uff0c\u6709\u5e7e\u500b\u91cd\u8981\u7684\u6ce8\u610f\u4e8b\u9805\uff1a<\/p>\n<ul>\n<li><strong>\u6027\u80fd\u8003\u91cf<\/strong>: \u591a\u8868\u806f\u5408\u67e5\u8a62\u53ef\u80fd\u6703\u5f71\u97ff\u67e5\u8a62\u6027\u80fd\uff0c\u7279\u5225\u662f\u7576\u6d89\u53ca\u5230\u5927\u91cf\u6578\u64da\u6642\u3002\u5efa\u8b70\u5728\u67e5\u8a62\u524d\u9032\u884c\u9069\u7576\u7684\u7d22\u5f15\u8a2d\u7f6e\u3002<\/li>\n<li><strong>\u907f\u514d\u91cd\u8907\u6578\u64da<\/strong>: \u4f7f\u7528 DISTINCT \u95dc\u9375\u5b57\u53ef\u4ee5\u5e6b\u52a9\u904e\u6ffe\u91cd\u8907\u7684\u7d50\u679c\u3002<\/li>\n<li><strong>\u7406\u89e3\u6578\u64da\u95dc\u806f<\/strong>: \u5728\u9032\u884c\u806f\u5408\u67e5\u8a62\u4e4b\u524d\uff0c\u5fc5\u9808\u6e05\u695a\u8868\u4e4b\u9593\u7684\u95dc\u806f\u6027\uff0c\u4ee5\u78ba\u4fdd\u67e5\u8a62\u7684\u6b63\u78ba\u6027\u3002<\/li>\n<li><strong>\u4f7f\u7528\u5225\u540d<\/strong>: \u5728\u67e5\u8a62\u4e2d\u4f7f\u7528\u8868\u7684\u5225\u540d\u53ef\u4ee5\u63d0\u9ad8\u53ef\u8b80\u6027\uff0c\u7279\u5225\u662f\u5728\u6d89\u53ca\u591a\u500b\u8868\u6642\u3002<\/li>\n<\/ul>\n<h2 id=\"%e5%af%a6%e9%9a%9b%e6%a1%88%e4%be%8b-jXVEIsNrqb\">\u5be6\u969b\u6848\u4f8b<\/h2>\n<p>\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b <code>products<\/code> \u8868\u548c\u4e00\u500b <code>categories<\/code> \u8868\uff0c\u6211\u5011\u60f3\u8981\u67e5\u8a62\u6bcf\u500b\u7522\u54c1\u53ca\u5176\u6240\u5c6c\u985e\u5225\u7684\u540d\u7a31\uff1a<\/p>\n<pre><code>SELECT products.product_name, categories.category_name\nFROM products\nINNER JOIN categories\nON products.category_id = categories.id;<\/code><\/pre>\n<p>\u9019\u6a23\u7684\u67e5\u8a62\u5c07\u8fd4\u56de\u6bcf\u500b\u7522\u54c1\u53ca\u5176\u5c0d\u61c9\u7684\u985e\u5225\u540d\u7a31\uff0c\u5e6b\u52a9\u7528\u6236\u66f4\u597d\u5730\u7406\u89e3\u7522\u54c1\u7684\u5206\u985e\u3002<\/p>\n<h2 id=\"%e7%b8%bd%e7%b5%90-jXVEIsNrqb\">\u7e3d\u7d50<\/h2>\n<p>MySQL \u7684\u591a\u8868\u806f\u5408\u67e5\u8a62\u662f\u4e00\u500b\u5f37\u5927\u7684\u5de5\u5177\uff0c\u53ef\u4ee5\u5e6b\u52a9\u7528\u6236\u5f9e\u591a\u500b\u8868\u4e2d\u63d0\u53d6\u548c\u6574\u5408\u6578\u64da\u3002\u901a\u904e\u7406\u89e3\u4e0d\u540c\u985e\u578b\u7684 JOIN\u3001\u638c\u63e1\u57fa\u672c\u8a9e\u6cd5\u4ee5\u53ca\u6ce8\u610f\u6027\u80fd\u548c\u6578\u64da\u95dc\u806f\u6027\uff0c\u4f7f\u7528\u8005\u53ef\u4ee5\u6709\u6548\u5730\u9032\u884c\u6578\u64da\u67e5\u8a62\u3002\u5c0d\u65bc\u9700\u8981\u9ad8\u6548\u6578\u64da\u8655\u7406\u7684\u61c9\u7528\u5834\u666f\uff0c\u9078\u64c7\u5408\u9069\u7684 <a href=\"https:\/\/server.hk\">VPS<\/a> \u89e3\u6c7a\u65b9\u6848\u5c07\u662f\u81f3\u95dc\u91cd\u8981\u7684\uff0c\u9019\u6a23\u53ef\u4ee5\u78ba\u4fdd\u6578\u64da\u5eab\u7684\u6027\u80fd\u548c\u7a69\u5b9a\u6027\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u63a2\u7d22 MySQL \u591a\u8868\u806f\u5408\u67e5\u8a62\u7684\u6280\u5de7\u8207\u6ce8\u610f\u4e8b\u9805\uff0c\u63d0\u5347\u6578\u64da\u6aa2\u7d22\u6548\u7387\uff0c\u512a\u5316\u67e5\u8a62\u6027\u80fd\uff0c\u907f\u514d\u5e38\u898b\u932f\u8aa4\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-75270","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/75270","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=75270"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/75270\/revisions"}],"predecessor-version":[{"id":75271,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/75270\/revisions\/75271"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=75270"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=75270"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=75270"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}