A question about table alias and "group by"

i have write a sql, but when put it into excution. some problem was happening...

the sql is like this:

select sth from

(select sth from A1 A2) B1,
(select sth from C1 C2) B2,
(select sth from B2 group by sth) B3

where

   B1.conditons compare with B2.conditions    And B2.condtions compare with B3.conditions

but it shows that the B2 table not exists messege. and who can tell me how drill infomation from B2?

too much thanks... ^_^ Received on Wed Oct 31 2007 - 01:56:50 CDT