Re: Quetions on Joins

Ron,
the idea is to provide a table where users can define filters. But it
this table may be as well empty.

Alex

Ron Johnson wrote:

>On Sun, 2003-08-31 at 11:56, Alex wrote:
>
>
>>Hi,
>>
>>I have a query where I want to filter out records from table_a if a
>>field in table_a matches in table table_b. Basically table_b defines the
>>filter.
>>
>>If table_b however is empty i dont get any results
>>
>>SELECT A.value_one FROM table_a AS A, table_b AS B WHERE  A.value_two <>
>>B.value_two;
>>or
>>SELECT A.value_one FROM table_a AS A, table_b AS B WHERE  A.value_two <>
>>B.value_two AND B.value_two NOTNULL;
>>
>>Only work if the there is a value in table_b.
>>Could anyone tell me if there is a way to do that ?
>>
>>
>
>If the filter is empty, how can you filter anything?
>
>
>
>>PS: I'd like to thank here persons who reply rather than sending the
>>message per mail.
>>
>>
>
>What does that mean?
>
>
>