Has everyone forgotten that since v4.0, MySQL has a multi-table delete 
statement?

http://dev.mysql.com/doc/refman/4.1/en/delete.html

Your original query was almost it  (Adrian was on the right track, too):

DELETE cart 
FROM cart 
LEFT JOIN products prod 
WHERE prod.id is null 
        or prod.online=0;

Sheeri, your answer would have worked for the deleted products but not for 
those product still in the database but whose online status was changed to 
0.

Shawn Green
Database Administrator
Unimin Corporation - Spruce Pine


sheeri kritzer <[EMAIL PROTECTED]> wrote on 01/25/2006 12:47:08 PM:

> The better way to do this would be to have the cart.prod_id be a
> foreign key field that references products.id (available as of
> 3.23.44) and use "ON CASCADE DELETE".  But that alters your schema,
> and you want to think very hard about the problems it might create
> (and do it with your data on a test server first, so you can see any
> warnings or errors).
> 
> -Sheeri
> 
> On 1/11/06, Adrian Bruce <[EMAIL PROTECTED]> wrote:
> >
> > IN MySQL 5 you could use a sub query(
> > http://dev.mysql.com/doc/refman/5.0/en/any-in-some-subqueries.html).
> >
> > However, i would try using a left join between cart and products and
> > then bring back the results where the products.id field is 'NULL'.
> > There may be a better way of doing this but that is what comes to mind
> > first.
> >
> > Ade
> >
> > Scott Haneda wrote:
> >
> > >4.0.18-standard-log
> > >
> > >I have a table cart and a table products
> > >
> > >Key is as follows:
> > >products.id = cart.prod_id
> > >
> > >The problem I have is we have decided to store the users cart, sowhen 
they
> > >come back it is still in the same state they left it.  Pretty 
> usual stuff so
> > >far.
> > >
> > >Two things can possible happen that would make this bad:
> > >1) product has been deleted
> > >2) product has been disabled.
> > >
> > >Just before I am checking the user out, I want to fix this scenario 
with a
> > >delete statement.  What I need to do is:
> > >
> > >DELETE FROM cart where cart.prod_id does not exist in the 
> products table, or
> > >where 'online' = 0.
> > >
> > >There is a user_id that I match on as well, but that does not 
entirely
> > >matter to this question.
> > >
> > >Deleting where online = 0 is simple, but deleting where there is 
> a lack of a
> > >matching product has me stumped.
> > >
> > >
> >
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> >
> >
> 
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