In the last episode (Nov 11), James Dyer said:
> If I create a table called foo like this:
> create table foo ( id1 int(11) , id2(int 11) );
>
> populate it with data and then try:
>
> SELECT * FROM foo WHERE id2=1 AND id2=2 (for example),
>
> I just get an empty set returned. An explain on the query gives an
> 'Impossible WHERE' message.
>
> Both id1 and id2 can have duplicate values in them, though the same
> combination of id1 and id2 cannot appear in the data (ie: id1=1,
> id2=1 ; id1=1, id2=2 is possible, id1=1, id2=1 ; id1=1, id2=1 is not
> possible), and it is possible that the values I search for will not
> be in the table at all.
>
> All I really want is to get the value for id1 where there are
> corresponding records which match all of my search parameters for
> id2.
You need a self-join.
SELECT foo1.id1
FROM foo AS foo1, foo AS foo2
WHERE foo1.id1=foo2.id1 AND foo1.id2=1 AND foo2.id2=2;
--
Dan Nelson
[EMAIL PROTECTED]
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