{"id":176,"date":"2014-07-31T22:47:16","date_gmt":"2014-07-31T14:47:16","guid":{"rendered":"http:\/\/tsui.ml\/?p=176"},"modified":"2014-12-14T11:31:00","modified_gmt":"2014-12-14T03:31:00","slug":"%e3%80%90%e8%bd%ac%e3%80%91%e5%9b%be%e8%a7%a3sql%e7%9a%84%e5%90%84%e7%a7%8d%e8%bf%9e%e6%8e%a5join","status":"publish","type":"post","link":"http:\/\/wp.tsui.ml\/?p=176","title":{"rendered":"\u3010\u8f6c\u3011\u56fe\u89e3SQL\u7684\u5404\u79cd\u8fde\u63a5JOIN"},"content":{"rendered":"<p style=\"color: #333333;\">\u3010\u8f6c\u81ea\u3011http:\/\/www.nowamagic.net\/librarys\/veda\/detail\/936<\/p>\n<p style=\"color: #333333;\">\u5bf9\u4e8eSQL\u7684Join\uff0c\u5728\u5b66\u4e60\u8d77\u6765\u53ef\u80fd\u662f\u6bd4\u8f83\u4e71\u7684\u3002\u6211\u4eec\u77e5\u9053\uff0cSQL\u7684Join\u8bed\u6cd5\u6709\u5f88\u591ainner\u7684\uff0c\u6709outer\u7684\uff0c\u6709left\u7684\uff0c\u6709\u65f6\u5019\uff0c\u5bf9\u4e8eSelect\u51fa\u6765\u7684\u7ed3\u679c\u96c6\u662f\u4ec0\u4e48\u6837\u5b50\u6709\u70b9\u4e0d\u662f\u5f88\u6e05\u695a\u3002Coding Horror\u4e0a\u6709\u4e00\u7bc7\u6587\u7ae0\uff08\u5b9e\u5728\u4e0d\u6e05\u695a\u4e3a\u4ec0\u4e48Coding Horror\u4e5f\u88ab\u5899\uff09\u901a\u8fc7 \u6587\u6c0f\u56fe Venn diagrams\u89e3\u91ca\u4e86SQL\u7684Join\u3002\u6211\u89c9\u5f97\u6e05\u695a\u6613\u61c2\uff0c\u8f6c\u8fc7\u6765\u3002<\/p>\n<p style=\"color: #333333;\">\u5047\u8bbe\u6211\u4eec\u6709\u4e24\u5f20\u8868\uff0cTable A\u662f\u5de6\u8fb9\u7684\u8868\uff0cTable B\u662f\u53f3\u8fb9\u7684\u8868<\/p>\n<p style=\"color: #333333;\"><!--more--><\/p>\n<p style=\"color: #333333;\">\u5176\u5404\u6709\u56db\u6761\u8bb0\u5f55\uff0c\u5176\u4e2d\u6709\u4e24\u6761\u8bb0\u5f55\u662f\u76f8\u540c\u7684\uff0c\u5982\u4e0b\u6240\u793a\uff1a<\/p>\n<pre class=\"brush: sql;\" style=\"color: #333333;\">id name       id  name\r\n-- ----       --  ----\r\n1  Pirate     1   Rutabaga\r\n2  Monkey     2   Pirate\r\n3  Ninja      3   Darth Vader\r\n4  Spaghetti  4   Ninja\r\n<\/pre>\n<p style=\"color: #333333;\">\u4e0b\u9762\u8ba9\u6211\u4eec\u6765\u770b\u770b\u4e0d\u540c\u7684Join\u4f1a\u4ea7\u751f\u4ec0\u4e48\u6837\u7684\u7ed3\u679c\u3002<\/p>\n<table style=\"color: #333333;\">\n<tbody>\n<tr>\n<td>\n<pre class=\"brush: sql;\">SELECT * FROM TableA INNER JOIN TableB\r\nON TableA.name = TableB.name\r\nid  name       id   name\r\n--  ----       --   ----\r\n1   Pirate     2    Pirate\r\n3   Ninja      4    Ninja\r\n<\/pre>\n<p><strong style=\"color: #444444;\">Inner join<\/strong><br \/>\n\u4ea7\u751f\u7684\u7ed3\u679c\u96c6\u4e2d\uff0c\u662fA\u548cB\u7684\u4ea4\u96c6\u3002<\/td>\n<td><img title=\"image of tsui.ml 1\" alt=\"tsui.ml|\u3010\u8f6c\u3011\u56fe\u89e3SQL\u7684\u5404\u79cd\u8fde\u63a5JOIN| 1\" decoding=\"async\" src=\"http:\/\/www.nowamagic.net\/librarys\/images\/201112\/2011_12_22_01.png\" width=\"250\" border=\"0\" \/><\/td>\n<\/tr>\n<tr>\n<td>\n<pre class=\"brush: sql;\">SELECT * FROM TableA FULL OUTER JOIN TableB\r\nON TableA.name = TableB.name\r\nid    name       id    name\r\n--    ----       --    ----\r\n1     Pirate     2     Pirate\r\n2     Monkey     null  null\r\n3     Ninja      4     Ninja\r\n4     Spaghetti  null  null\r\nnull\tnull\t1     Rutabaga\r\nnull\tnull\t3     Darth Vader\r\n<\/pre>\n<p><strong style=\"color: #444444;\">Full outer join<\/strong>\u00a0\u4ea7\u751fA\u548cB\u7684\u5e76\u96c6\u3002\u4f46\u662f\u9700\u8981\u6ce8\u610f\u7684\u662f\uff0c\u5bf9\u4e8e\u6ca1\u6709\u5339\u914d\u7684\u8bb0\u5f55\uff0c\u5219\u4f1a\u4ee5null\u505a\u4e3a\u503c\u3002<\/td>\n<td><img title=\"image of tsui.ml 2\" alt=\"tsui.ml|\u3010\u8f6c\u3011\u56fe\u89e3SQL\u7684\u5404\u79cd\u8fde\u63a5JOIN| 2\" decoding=\"async\" src=\"http:\/\/www.nowamagic.net\/librarys\/images\/201112\/2011_12_22_02.png\" width=\"250\" border=\"0\" \/><\/td>\n<\/tr>\n<tr>\n<td>\n<pre class=\"brush: sql;\">SELECT * FROM TableA LEFT OUTER JOIN TableB ON TableA.name = TableB.name\r\nid  name       id    name\r\n--  ----       --    ----\r\n1   Pirate     2     Pirate\r\n2   Monkey\t\tnull\tnull\r\n3   Ninja      4     Ninja\r\n4   Spaghetti\tnull\tnull\r\n<\/pre>\n<p><strong style=\"color: #444444;\">Left outer join<\/strong>\u00a0\u4ea7\u751f\u8868A\u7684\u5b8c\u5168\u96c6\uff0c\u800cB\u8868\u4e2d\u5339\u914d\u7684\u5219\u6709\u503c\uff0c\u6ca1\u6709\u5339\u914d\u7684\u5219\u4ee5null\u503c\u53d6\u4ee3\u3002<\/td>\n<td><img title=\"image of tsui.ml 3\" alt=\"tsui.ml|\u3010\u8f6c\u3011\u56fe\u89e3SQL\u7684\u5404\u79cd\u8fde\u63a5JOIN| 3\" decoding=\"async\" src=\"http:\/\/www.nowamagic.net\/librarys\/images\/201112\/2011_12_22_03.png\" width=\"250\" border=\"0\" \/><\/td>\n<\/tr>\n<tr>\n<td>\n<pre class=\"brush: sql;\">SELECT * FROM TableA LEFT OUTER JOIN TableB ON TableA.name = TableB.name WHERE TableB.id IS null\r\nid  name       id     name\r\n--  ----       --     ----\r\n2   Monkey\tnull\tnull\r\n4   Spaghetti\tnull\tnull\r\n<\/pre>\n<p>\u4ea7\u751f\u5728A\u8868\u4e2d\u6709\u800c\u5728B\u8868\u4e2d\u6ca1\u6709\u7684\u96c6\u5408\u3002<\/td>\n<td><img title=\"image of tsui.ml 4\" alt=\"tsui.ml|\u3010\u8f6c\u3011\u56fe\u89e3SQL\u7684\u5404\u79cd\u8fde\u63a5JOIN| 4\" decoding=\"async\" src=\"http:\/\/www.nowamagic.net\/librarys\/images\/201112\/2011_12_22_04.png\" width=\"250\" border=\"0\" \/><\/td>\n<\/tr>\n<tr>\n<td>\n<pre class=\"brush: sql;\">SELECT * FROM TableA FULL OUTER JOIN TableB ON TableA.name = TableB.name WHERE TableA.id IS null OR TableB.id IS null\r\nid    name       id    name\r\n--    ----       --    ----\r\n2     Monkey\tnull\tnull\r\n4     Spaghetti\tnull\tnull\r\nnull\tnull\t1     Rutabaga\r\nnull\tnull\t3     Darth Vader\r\n<\/pre>\n<p>\u4ea7\u751fA\u8868\u548cB\u8868\u90fd\u6ca1\u6709\u51fa\u73b0\u7684\u6570\u636e\u96c6\u3002<\/td>\n<td><img title=\"image of tsui.ml 5\" alt=\"tsui.ml|\u3010\u8f6c\u3011\u56fe\u89e3SQL\u7684\u5404\u79cd\u8fde\u63a5JOIN| 5\" decoding=\"async\" src=\"http:\/\/www.nowamagic.net\/librarys\/images\/201112\/2011_12_22_05.png\" width=\"250\" border=\"0\" \/><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p style=\"color: #333333;\">\u8fd8\u9700\u8981\u6ce8\u518c\u7684\u662f\u6211\u4eec\u8fd8\u6709\u4e00\u4e2a\u662f&#8221;\u4ea4\u5dee\u96c6&#8221; cross join, \u8fd9\u79cdJoin\u6ca1\u6709\u529e\u6cd5\u7528\u6587\u5f0f\u56fe\u8868\u793a\uff0c\u56e0\u4e3a\u5176\u5c31\u662f\u628a\u8868A\u548c\u8868B\u7684\u6570\u636e\u8fdb\u884c\u4e00\u4e2aN*M\u7684\u7ec4\u5408\uff0c\u5373\u7b1b\u5361\u5c14\u79ef\u3002\u8868\u8fbe\u5f0f\u5982\u4e0b\uff1a<\/p>\n<pre class=\"brush: sql;\" style=\"color: #333333;\">SELECT * FROM TableA\r\nCROSS JOIN TableB\r\n<\/pre>\n<p style=\"color: #333333;\">\u8fd9\u4e2a\u7b1b\u5361\u5c14\u4e58\u79ef\u4f1a\u4ea7\u751f 4 x 4 = 16 \u6761\u8bb0\u5f55\uff0c\u4e00\u822c\u6765\u8bf4\uff0c\u6211\u4eec\u5f88\u5c11\u7528\u5230\u8fd9\u4e2a\u8bed\u6cd5\u3002\u4f46\u662f\u6211\u4eec\u5f97\u5c0f\u5fc3\uff0c\u5982\u679c\u4e0d\u662f\u4f7f\u7528\u5d4c\u5957\u7684select\u8bed\u53e5\uff0c\u4e00\u822c\u7cfb\u7edf\u90fd\u4f1a\u4ea7\u751f\u7b1b\u5361\u5c14\u4e58\u79ef\u7136\u518d\u505a\u8fc7\u6ee4\u3002\u8fd9\u662f\u5bf9\u4e8e\u6027\u80fd\u6765\u8bf4\u662f\u975e\u5e38\u5371\u9669\u7684\uff0c\u5c24\u5176\u662f\u8868\u5f88\u5927\u7684\u65f6\u5019\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u3010\u8f6c\u81ea\u3011http:\/\/www.nowamagic.net\/librarys\/veda\/detail\/936 \u5bf9 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[10],"tags":[],"views":685,"_links":{"self":[{"href":"http:\/\/wp.tsui.ml\/index.php?rest_route=\/wp\/v2\/posts\/176"}],"collection":[{"href":"http:\/\/wp.tsui.ml\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/wp.tsui.ml\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/wp.tsui.ml\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/wp.tsui.ml\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=176"}],"version-history":[{"count":4,"href":"http:\/\/wp.tsui.ml\/index.php?rest_route=\/wp\/v2\/posts\/176\/revisions"}],"predecessor-version":[{"id":180,"href":"http:\/\/wp.tsui.ml\/index.php?rest_route=\/wp\/v2\/posts\/176\/revisions\/180"}],"wp:attachment":[{"href":"http:\/\/wp.tsui.ml\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=176"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/wp.tsui.ml\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=176"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/wp.tsui.ml\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=176"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}