数据库查询问题   在线等
table1有字段A,B, 
 table2有字段C,D 
 select   a,b   from   table1   where   a   =   1 
 select   c,d   from   table2   where   c   =2 
 这两条语句能不能写在一条查询语句里   做为一个结果集合返回
------解决方案--------------------(select a,b from table1 where a = 1) 
 union 
 (select c as a,d as b from table2 where c =2)
------解决方案--------------------如果   
 table1有字段A,和 table2有字段C    
 table1有字段B,和 table2有字段D    
 类型是一致.   
 这样就可以了 
 select a,b from table1 where a = 1 
 union all 
 select c,d from table2 where c =2