{"id":144091,"date":"2024-11-01T05:30:28","date_gmt":"2024-10-31T21:30:28","guid":{"rendered":"https:\/\/server.hk\/cnblog\/144091\/"},"modified":"2024-11-01T05:30:28","modified_gmt":"2024-10-31T21:30:28","slug":"sql-%e4%b8%ad%e9%97%9c%e6%96%bc-join-%e8%81%af%e5%90%88%e6%9f%a5%e8%a9%a2%e4%b8%ad%e7%9a%84%e9%97%9c%e9%8d%b5%e8%aa%9e%e6%b3%95","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/144091\/","title":{"rendered":"SQL \u4e2d\u95dc\u65bc JOIN \u806f\u5408\u67e5\u8a62\u4e2d\u7684\u95dc\u9375\u8a9e\u6cd5"},"content":{"rendered":"<h1 id=\"sql-%e4%b8%ad%e9%97%9c%e6%96%bc-join-%e8%81%af%e5%90%88%e6%9f%a5%e8%a9%a2%e4%b8%ad%e7%9a%84%e9%97%9c%e9%8d%b5%e8%aa%9e%e6%b3%95-bPzvglSqQt\">SQL \u4e2d\u95dc\u65bc JOIN \u806f\u5408\u67e5\u8a62\u4e2d\u7684\u95dc\u9375\u8a9e\u6cd5<\/h1>\n<p>\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\u76f8\u95dc\u8cc7\u6599\u6642\uff0cJOIN \u806f\u5408\u67e5\u8a62\u4fbf\u6210\u70ba\u4e86\u4e00\u500b\u4e0d\u53ef\u6216\u7f3a\u7684\u5de5\u5177\u3002\u672c\u6587\u5c07\u6df1\u5165\u63a2\u8a0e SQL \u4e2d JOIN \u7684\u95dc\u9375\u8a9e\u6cd5\u53ca\u5176\u4f7f\u7528\u65b9\u6cd5\u3002<\/p>\n<h2 id=\"join-%e7%9a%84%e5%9f%ba%e6%9c%ac%e6%a6%82%e5%bf%b5-bPzvglSqQt\">JOIN \u7684\u57fa\u672c\u6982\u5ff5<\/h2>\n<p>JOIN \u662f\u4e00\u7a2e SQL \u8a9e\u53e5\uff0c\u7528\u65bc\u6839\u64da\u5169\u500b\u6216\u591a\u500b\u8cc7\u6599\u8868\u4e4b\u9593\u7684\u95dc\u806f\u4f86\u67e5\u8a62\u8cc7\u6599\u3002\u900f\u904e JOIN\uff0c\u6211\u5011\u53ef\u4ee5\u5c07\u4e0d\u540c\u8cc7\u6599\u8868\u4e2d\u7684\u8cc7\u6599\u7d50\u5408\u5728\u4e00\u8d77\uff0c\u5f62\u6210\u4e00\u500b\u66f4\u5b8c\u6574\u7684\u8cc7\u6599\u96c6\u3002JOIN \u7684\u4e3b\u8981\u985e\u578b\u5305\u62ec INNER JOIN\u3001LEFT JOIN\u3001RIGHT JOIN \u548c FULL OUTER JOIN\u3002<\/p>\n<h2 id=\"%e4%b8%8d%e5%90%8c%e9%a1%9e%e5%9e%8b%e7%9a%84-join-bPzvglSqQt\">\u4e0d\u540c\u985e\u578b\u7684 JOIN<\/h2>\n<h3 id=\"1-inner-join-bPzvglSqQt\">1. INNER JOIN<\/h3>\n<p>INNER JOIN \u662f\u6700\u5e38\u7528\u7684 JOIN \u985e\u578b\uff0c\u5b83\u53ea\u8fd4\u56de\u5169\u500b\u8cc7\u6599\u8868\u4e2d\u5339\u914d\u7684\u884c\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u4f7f\u7528 INNER JOIN \u7684\u7bc4\u4f8b\uff1a<\/p>\n<pre><code>SELECT a.name, b.order_date\nFROM customers a\nINNER JOIN orders b ON a.customer_id = b.customer_id;<\/code><\/pre>\n<p>\u5728\u9019\u500b\u4f8b\u5b50\u4e2d\uff0c\u6211\u5011\u5f9e customers \u8868\u548c orders \u8868\u4e2d\u9078\u53d6\u5ba2\u6236\u540d\u7a31\u548c\u8a02\u55ae\u65e5\u671f\uff0c\u50c5\u8fd4\u56de\u90a3\u4e9b\u6709\u8a02\u55ae\u7684\u5ba2\u6236\u3002<\/p>\n<h3 id=\"2-left-join-bPzvglSqQt\">2. LEFT JOIN<\/h3>\n<p>LEFT JOIN \u8fd4\u56de\u5de6\u5074\u8cc7\u6599\u8868\u7684\u6240\u6709\u884c\uff0c\u5373\u4f7f\u53f3\u5074\u8cc7\u6599\u8868\u4e2d\u6c92\u6709\u5339\u914d\u7684\u884c\u3002\u4ee5\u4e0b\u662f LEFT JOIN \u7684\u7bc4\u4f8b\uff1a<\/p>\n<pre><code>SELECT a.name, b.order_date\nFROM customers a\nLEFT JOIN orders b ON a.customer_id = b.customer_id;<\/code><\/pre>\n<p>\u9019\u500b\u67e5\u8a62\u5c07\u8fd4\u56de\u6240\u6709\u5ba2\u6236\u7684\u540d\u7a31\uff0c\u4e26\u4e14\u5982\u679c\u67d0\u4e9b\u5ba2\u6236\u6c92\u6709\u8a02\u55ae\uff0c\u5247\u8a02\u55ae\u65e5\u671f\u5c07\u986f\u793a\u70ba NULL\u3002<\/p>\n<h3 id=\"3-right-join-bPzvglSqQt\">3. RIGHT JOIN<\/h3>\n<p>RIGHT JOIN \u8207 LEFT JOIN \u76f8\u53cd\uff0c\u5b83\u8fd4\u56de\u53f3\u5074\u8cc7\u6599\u8868\u7684\u6240\u6709\u884c\u3002\u4ee5\u4e0b\u662f RIGHT JOIN \u7684\u7bc4\u4f8b\uff1a<\/p>\n<pre><code>SELECT a.name, b.order_date\nFROM customers a\nRIGHT JOIN orders b ON a.customer_id = b.customer_id;<\/code><\/pre>\n<p>\u9019\u500b\u67e5\u8a62\u5c07\u8fd4\u56de\u6240\u6709\u8a02\u55ae\u7684\u65e5\u671f\uff0c\u4e26\u4e14\u5982\u679c\u67d0\u4e9b\u8a02\u55ae\u6c92\u6709\u5c0d\u61c9\u7684\u5ba2\u6236\uff0c\u5247\u5ba2\u6236\u540d\u7a31\u5c07\u986f\u793a\u70ba NULL\u3002<\/p>\n<h3 id=\"4-full-outer-join-bPzvglSqQt\">4. FULL OUTER JOIN<\/h3>\n<p>FULL OUTER JOIN \u8fd4\u56de\u5169\u500b\u8cc7\u6599\u8868\u4e2d\u7684\u6240\u6709\u884c\uff0c\u7121\u8ad6\u662f\u5426\u6709\u5339\u914d\u3002\u4ee5\u4e0b\u662f FULL OUTER JOIN \u7684\u7bc4\u4f8b\uff1a<\/p>\n<pre><code>SELECT a.name, b.order_date\nFROM customers a\nFULL OUTER JOIN orders b ON a.customer_id = b.customer_id;<\/code><\/pre>\n<p>\u9019\u500b\u67e5\u8a62\u5c07\u8fd4\u56de\u6240\u6709\u5ba2\u6236\u548c\u6240\u6709\u8a02\u55ae\uff0c\u5c0d\u65bc\u6c92\u6709\u5339\u914d\u7684\u884c\uff0c\u5c07\u986f\u793a NULL\u3002<\/p>\n<h2 id=\"join-%e7%9a%84%e4%bd%bf%e7%94%a8%e6%b3%a8%e6%84%8f%e4%ba%8b%e9%a0%85-bPzvglSqQt\">JOIN \u7684\u4f7f\u7528\u6ce8\u610f\u4e8b\u9805<\/h2>\n<ul>\n<li>\u78ba\u4fdd\u5728 JOIN \u689d\u4ef6\u4e2d\u4f7f\u7528\u6b63\u78ba\u7684\u6b04\u4f4d\uff0c\u4ee5\u907f\u514d\u4e0d\u5fc5\u8981\u7684\u8cc7\u6599\u91cd\u8907\u3002<\/li>\n<li>\u4f7f\u7528\u9069\u7576\u7684\u7d22\u5f15\u53ef\u4ee5\u63d0\u9ad8 JOIN \u67e5\u8a62\u7684\u6027\u80fd\u3002<\/li>\n<li>\u5728\u9032\u884c\u591a\u8868 JOIN \u6642\uff0c\u6ce8\u610f\u67e5\u8a62\u7684\u53ef\u8b80\u6027\uff0c\u9069\u7576\u4f7f\u7528\u5225\u540d\u53ef\u4ee5\u4f7f\u67e5\u8a62\u66f4\u6e05\u6670\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b8%bd%e7%b5%90-bPzvglSqQt\">\u7e3d\u7d50<\/h2>\n<p>JOIN \u662f SQL \u4e2d\u4e00\u500b\u5f37\u5927\u7684\u529f\u80fd\uff0c\u80fd\u5920\u5e6b\u52a9\u7528\u6236\u5f9e\u591a\u500b\u8cc7\u6599\u8868\u4e2d\u63d0\u53d6\u548c\u6574\u5408\u8cc7\u6599\u3002\u900f\u904e INNER JOIN\u3001LEFT JOIN\u3001RIGHT JOIN \u548c FULL OUTER JOIN \u7b49\u4e0d\u540c\u985e\u578b\u7684 JOIN\uff0c\u4f7f\u7528\u8005\u53ef\u4ee5\u9748\u6d3b\u5730\u6839\u64da\u9700\u6c42\u67e5\u8a62\u8cc7\u6599\u3002\u4e86\u89e3\u9019\u4e9b JOIN \u7684\u95dc\u9375\u8a9e\u6cd5\u548c\u4f7f\u7528\u60c5\u5883\uff0c\u5c0d\u65bc\u8cc7\u6599\u5eab\u7ba1\u7406\u548c\u8cc7\u6599\u5206\u6790\u81f3\u95dc\u91cd\u8981\u3002<\/p>\n<p>\u5982\u679c\u60a8\u5c0d\u65bc\u8cc7\u6599\u5eab\u7ba1\u7406\u6709\u9032\u4e00\u6b65\u7684\u9700\u6c42\uff0c\u8003\u616e\u4f7f\u7528 <a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a> \u4f86\u642d\u5efa\u60a8\u7684\u8cc7\u6599\u5eab\u74b0\u5883\uff0c\u4eab\u53d7\u66f4\u9ad8\u6548\u7684\u8cc7\u6599\u8655\u7406\u80fd\u529b\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u63a2\u7d22 SQL \u4e2d JOIN \u806f\u5408\u67e5\u8a62\u7684\u95dc\u9375\u8a9e\u6cd5\uff0c\u4e86\u89e3\u5982\u4f55\u6709\u6548\u5730\u7d50\u5408\u591a\u500b\u8cc7\u6599\u8868\u4ee5\u7372\u53d6\u6240\u9700\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-144091","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/144091","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=144091"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/144091\/revisions"}],"predecessor-version":[{"id":144092,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/144091\/revisions\/144092"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=144091"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=144091"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=144091"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}