我现在有3个表:User表 Expert表 Enterprise表
怎么通过User表中的UserType来确定是查找Expert表还是查找Enterprise表
并且能生成一个视图
------解决方案--------------------
- SQL code
--> 测试数据：@Userdeclare @User table([ID] int,[Name] varchar(1),[UserType] int)insert @Userselect 1,'a',1 union allselect 2,'b',1 union allselect 3,'c',2 union allselect 4,'d',2--> 测试数据：@Expertdeclare @Expert table([ID] int,[c1] varchar(1))insert @Expertselect 1,'a' union allselect 2,'b' union allselect 3,'c' union allselect 4,'d'--> 测试数据：@Enterprisedeclare @Enterprise table([ID] int,[c1] varchar(1))insert @Enterpriseselect 5,'a' union allselect 6,'b' union allselect 7,'c' union allselect 8,'d'select * from @User aLEFT JOIN @Expert b ON a.[UserType]=1 AND a.name=b.[c1]LEFT JOIN @Enterprise c ON a.[UserType]=2 AND a.name=c.[c1] /*ID Name UserType ID c1 ID c1----------- ---- ----------- ----------- ---- ----------- ----1 a 1 1 a NULL NULL2 b 1 2 b NULL NULL3 c 2 NULL NULL 7 c4 d 2 NULL NULL 8 d*/