G .Net wrote:

> Can anybody tell me the sql query I need to find the following:
>
> I have two tables A and B. A is a parent to B.
>
> I need to find the rows in B which do not have a corresponding foreign key
> value to a row in A.

"Ed Murphy" <emurphy42@socal.rr.com> wrote in message
news:S8Ddh.47590$Fg.43899@tornado.socal.rr.com...
>G .Net wrote:
>
>> Can anybody tell me the sql query I need to find the following:
>>
>> I have two tables A and B. A is a parent to B.
>>
>> I need to find the rows in B which do not have a corresponding foreign
>> key value to a row in A.
>
> select B.primary_key
> from B
> left outer join A on B.foreign_key = A.primary_key
> where A.primary_key is null
>
> Should this situation be allowed? If not, then (after cleaning up all
> existing cases) you should enforce it in the table definitions. (I'll
> let someone else expand on that, rather than risk getting it wrong.)

On Wed, 6 Dec 2006 11:47:37 -0000, "G .Net" <nodamnspam@email.com> wrote:

>Hi
>
>Can anybody tell me the sql query I need to find the following:
>
>I have two tables A and B. A is a parent to B.
>
>I need to find the rows in B which do not have a corresponding foreign key
>value to a row in A.
>
>Thanks in advance
>
>G