再次问一个SQL

Question

发表于：2007-12-21 15:15:35 楼主 
c1{ 
a1     char(7)//   （主键） 
a2           char(8)         //（主键） 
a3           int         //     数字定义0，1，2，3   } 
c2{ 
a1     char(7)//   （主键） 
a2   char(8)   //（主键） 
b3       int           //   } 要求：删除c2表中而且C1.a3=3的所有数据； 
如C1表 
a1                               a2                   a3 
1000001                   00000001                     0 
1000002                   00000001                     3 
C2表 
a1                               a2                   b3 
1000001                     00000001                   2 
1000001                     00000002                   2 
1000002                     00000001                   2 
结果应该只删除了C2表的第三条数据

Answer 1

delete from c2 where a1 in (select distinct a1 from c1 where a3=3)