Rick, thanks for the idea but actually it wouldnt work :(
take a look:
mysql> delete answers
-> from exam e, questions q, answers a
-> where a.question_id=q.question_id and q.exam_id=e.exam_id;
ERROR 1064: You have an error in your SQL syntax near 'answers
from exam e, questions q, exam_an' at line 1
so i think the problem is that you cant do "DELETE something FROM..." i
think the solution is more like the one Bill Morrow proposed, even though he
is using a subselect and i am using my sql.
Any ideas?
thanks for the help so far,
andres
----- Original Message -----
From: "Rick Emery" <[EMAIL PROTECTED]>
To: "Andr?s Felipe Hern?ndez" <[EMAIL PROTECTED]>
Cc: <[EMAIL PROTECTED]>
Sent: Monday, March 25, 2002 12:03 PM
Subject: RE: [PHP-DB] delete statement question
> this solution will not work for mysql databases, as mysql does not support
> sub-selects
>
> -----Original Message-----
> From: Bill Morrow [mailto:[EMAIL PROTECTED]]
> Sent: Monday, March 25, 2002 2:02 PM
> To: Andr?s Felipe Hern?ndez
> Cc: [EMAIL PROTECTED]
> Subject: Re: [PHP-DB] delete statement question
>
>
> On Mon, Mar 25, 2002 at 02:42:08PM -0800, Andr?s Felipe Hern?ndez wrote:
> > Hi, I hope you can help me with this:
> >
> > I have these 3 tables.
> >
> > exam (
> > exam_id
> > )
> >
> > questions (
> > question_id
> > exam_id
> > )
> >
> > answers (
> > answer_id
> > question_id
> > )
> >
> > I am wondering if i can delete all the rows for answers linked to a
given
> > exam using only one delete statement.
> >
> > Thanks in advance,
> >
> > andres
> >
>
> delete answers
> where question_id in (select question_id from questions where exam_id=X)
>
> I assume there isn't a one-to-one relationship between questions and
> answers? If there is, your database is overnormalized.
>
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