{"id":163008,"date":"2020-10-02T21:27:18","date_gmt":"2020-10-02T13:27:18","guid":{"rendered":"http:\/\/4563.org\/?p=163008"},"modified":"2020-10-02T21:27:18","modified_gmt":"2020-10-02T13:27:18","slug":"sql-%e4%bc%98%e5%8c%96%e6%b1%82%e6%8c%87%e5%af%bc","status":"publish","type":"post","link":"http:\/\/4563.org\/?p=163008","title":{"rendered":"sql \u4f18\u5316\u6c42\u6307\u5bfc"},"content":{"rendered":"<div>\n<div>\n<div>\n<h1>                  sql \u4f18\u5316\u6c42\u6307\u5bfc               <\/h1>\n<p> <\/p>\n<div>\n<div> <span>\u8cc7\u6df1\u5927\u4f6c : seagull7558 <\/span>  <span><i><\/i> 0<\/span> <\/div>\n<div> <\/div>\n<\/p><\/div>\n<\/p><\/div>\n<\/p><\/div>\n<div isfirst=\"1\"> <\/p>\n<p>SELECT X,X,X,X FROM A LEFT JOIN B ON a.id = b.a_id GROUP BY b.spell_name ORDER BY b.code<\/p>\n<p>\u7c7b\u4f3c\u4e8e\u8fd9\u79cd\u67e5 A \u8868 \u4f46\u4f7f\u7528 B \u8868\u5b57\u6bb5\u505a\u6392\u5e8f\u548c\u5206\u7ec4\u7684 SQL \u8be5\u5982\u4f55\u6dfb\u52a0\u7d22\u5f15\u5462?<\/p>\n<\/p><\/div>\n<div> <b>\u5927\u4f6c\u6709\u8a71\u8aaa<\/b> (<span>5<\/span>)        <\/div>\n<div> <\/div>\n<\/p><\/div>\n<\/p><\/div>\n<ul>\n<li data-pid=\"3550807\" data-uid=\"2\">\n<div>\n<div>\n<div> <span>\u8cc7\u6df1\u5927\u4f6c : bigNewsMaker <\/span>  <\/div>\n<div> <i title=\"\u5f15\u7528\"><\/i>  <span>          <\/span> <\/div>\n<\/p><\/div>\n<div>                                                             \u6539\u6210 right join\uff0c\u7136\u540e\u5728 b \u8868\u4e0a\u52a0\u7d22\u5f15\uff1f                                                            <\/div>\n<\/p><\/div>\n<\/li>\n<li data-pid=\"3550808\" data-uid=\"2\">\n<div>\n<div>\n<div> <span>\u8cc7\u6df1\u5927\u4f6c : fuyufjh <\/span>  <\/div>\n<div> <i title=\"\u5f15\u7528\"><\/i>  <span>          <\/span> <\/div>\n<\/p><\/div>\n<div>                                                             * \u6539\u6210 inner join \uff08 inner join \u53ef\u4ee5\u5de6\u53f3\u5bf9\u8c03\uff0cleft join \u4e0d\u53ef\u4ee5\uff09\uff0c\u7136\u540e\u5728 b.spell_name \u4e0a\u52a0\u7d22\u5f15<br \/>* \u53e6\u5916\uff0c\u8fd9\u662f\u4e00\u4e2a\u5178\u578b\u7684\u5206\u6790\u578b\u67e5\u8be2\uff0c\u5efa\u8bae\u5bfc\u5230\u5176\u4ed6\u5206\u6790\u578b\u6570\u636e\u5e93\u91cc\u505a                                                            <\/div>\n<\/p><\/div>\n<\/li>\n<li data-pid=\"3550809\" data-uid=\"2\">\n<div>\n<div>\n<div> <span>\u8cc7\u6df1\u5927\u4f6c : maigebaoer <\/span>  <\/div>\n<div> <i title=\"\u5f15\u7528\"><\/i>  <span>          <\/span> <\/div>\n<\/p><\/div>\n<div>                                                             \u4f60\u5148\u628a b \u8868 group\uff0corder \u540e\u7684\u53d6\u51fa\u6765\uff0c\u518d\u548c a \u8868 join\uff0c\u770b\u770b\u5982\u4f55\uff1f                                                            <\/div>\n<\/p><\/div>\n<\/li>\n<li data-pid=\"3550810\" data-uid=\"2\">\n<div>\n<div>\n<div> <span>\u8cc7\u6df1\u5927\u4f6c : hooopo <\/span>  <\/div>\n<div> <i title=\"\u5f15\u7528\"><\/i>  <span>          <\/span> <\/div>\n<\/p><\/div>\n<div>                                                             \u4e00\u5b9a\u662f\u5148\u6392\u5e8f\u540e join \u54af                                                            <\/div>\n<\/p><\/div>\n<\/li>\n<li data-pid=\"3550811\" data-uid=\"2\">\n<div>\n<div>\n<div> <span>\u8cc7\u6df1\u5927\u4f6c : l00t <\/span>  <\/div>\n<div> <i title=\"\u5f15\u7528\"><\/i>  <span>          <\/span> <\/div>\n<\/p><\/div>\n<div>                                                             \u52a0\u5728\u5173\u8054\u6761\u4ef6\u4e0a\uff0c\u4e5f\u5c31\u662f ID \u3002group by \u7684\u5b57\u6bb5\u4e0d\u7528\u8003\u8651\uff0c\u8fd9\u90e8\u5206\u4e0d\u9700\u8981\u7d22\u5f15\u3002<\/p>\n<p>\u4e0a\u7684\u4e00\u4e9b\u56de\u7b54\u7b80\u76f4\u4e0d\u61c2 SQL\uff0cleft join \u548c right join \/ inner join \u538b\u6839\u4e0d\u7b49\u4ef7\uff0c\u51fa\u6765\u7684\u7ed3\u679c\u96c6\u90fd\u4e0d\u4e00\u6837\uff0c\u80fd\u968f\u4fbf\u6362\uff1f                                                            <\/p><\/div>\n<\/p><\/div>\n<\/li>\n<li>\n","protected":false},"excerpt":{"rendered":"<p>sql \u4f18\u5316\u6c42\u6307\u5bfc \u8cc7\u6df1\u5927\u4f6c : &hellip;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[],"tags":[],"_links":{"self":[{"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts\/163008"}],"collection":[{"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=163008"}],"version-history":[{"count":0,"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts\/163008\/revisions"}],"wp:attachment":[{"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=163008"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=163008"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=163008"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}