Re: Why the "where NOT EXISTS" does not work?

From: Ed Prochak <edprochak_at_magicinterface.com>
Date: Wed, 24 Oct 2001 06:07:30 GMT
Message-ID: <3BD685AA.4BC3DAF5@magicinterface.com>

C Chang wrote:
>
> I have 2 tables say A_table, B_table. They both have some common
> columns. The A_Table has some rows that with the column not appearing
> in B_table. I tried to use following to find out what appears in
> A_talbe but not in B_table.
> select a
> from A_table
> where NOT EXISTS
> ( select a
> from B_table
> where ..);

HERE ^^^^^^^^^^^^^^^

is your problem. You have to supply a proper WHERE clause

> and it always return 0 row. What went wrong? Need Help Thanks.
>
> C Chang
Received on Wed Oct 24 2001 - 01:07:30 CDT