Is a sub-select more efficient than an outer join?
SELECT cust_id FROM customers LEFT JOIN orders on customers.cust_id =
orders.cust_id WHERE orders.cust_id IS NULL;
Or am I missing something (as usual)?
Regards,
Jerry Schwartz
Global Information Incorporated
195 Farmington Ave.
Farmington, CT 06032
860.674.8796 / FAX: 860.674.8341
> -----Original Message-----
> From: Waldemar Jankowski [mailto:waldemar@stripped]
> Sent: Friday, October 20, 2006 1:53 PM
> To: afan@stripped
> Cc: mysql@stripped
> Subject: Re: help with query: select customers that ARO NOT
> in orders table
>
> On Fri, 20 Oct 2006, afan@stripped wrote:
>
> > hi to all,
> > I have table customers (PK cust_id)
> > I have table orders (PK order_id, FK cust_id)
> >
> > I need query that will selecct all customers from
> 'customers' they don't
> > have any order, there is not their cust_id in 'orders'.
> >
> > couls somebody help me?
> >
> > thanks.
> >
> > -afan
>
> I think the most explicit way is with a sub select:
>
> select cust_id from customers where
> cust_id not in
> (select cust_id from orders);
>
> -w
>
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