C++博客-gan-随笔分类-MySqlhttp://www.cppblog.com/gan/category/8801.htmlzh-cnTue, 11 Nov 2008 06:41:03 GMTTue, 11 Nov 2008 06:41:03 GMT60MySql 的外连接http://www.cppblog.com/gan/archive/2008/11/11/66586.htmlganganTue, 11 Nov 2008 03:14:00 GMThttp://www.cppblog.com/gan/archive/2008/11/11/66586.htmlhttp://www.cppblog.com/gan/comments/66586.htmlhttp://www.cppblog.com/gan/archive/2008/11/11/66586.html#Feedback0http://www.cppblog.com/gan/comments/commentRss/66586.htmlhttp://www.cppblog.com/gan/services/trackbacks/66586.htmlSELECT *
FROM Student,SC
WHERE Student.Sno=SC.Sno(*);

在MySql中不可行，说某些数据库中用'+'而不是'*'，括号中换用'+'之后仍然无效。Google后解决，记下笔记。

左外连接: 以Student表（Student表行数较多）为主体列出，若SC表（比Student表行数少）无对应项，则为空值，故左连接NULL应该出现右边。
select * from Student left outer join SC on Student.Sno=SC.Sno;


右外连接：以SC表为主体列出，NULL出现在左边。
select * from Student right outer join SC on Student.Sno=SC.Sno;


gan 2008-11-11 11:14 发表评论
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