Sagi Bashari <[EMAIL PROTECTED]> wrote: > Michael Stassen wrote: > >> No, you can't use an alias in the WHERE clause. Even if you could, >> you'd have a problem here. The WHERE clause is used to decide which >> rows to look at in advance of any calculations. You're asking mysql >> to count the rows which match the WHERE clause, but you're also asking >> it to determine the WHERE match according to the count. See the >> problem? That's why you can't use COUNT in the WHERE clause. >> Fortunately, we have the HAVING clause for this purpose. What you >> need is >> >> SELECT products.id >> FROM products, orders >> WHERE orders.product_id = products.id >> GROUP BY products.id >> HAVING COUNT(orders.id) >= products.quantity > > > Tried that, see my original message - didn't really work: ERROR 1054: > Unknown column 'products.quantity' in 'having clause' > > However, once I added products.quantity to the SELECT list (before I > only selected the id) it worked. Strange. >
In the HAVING clause you can refer to column or alias that is present in the select list. -- For technical support contracts, goto https://order.mysql.com/?ref=ensita This email is sponsored by Ensita.net http://www.ensita.net/ __ ___ ___ ____ __ / |/ /_ __/ __/ __ \/ / Egor Egorov / /|_/ / // /\ \/ /_/ / /__ [EMAIL PROTECTED] /_/ /_/\_, /___/\___\_\___/ MySQL AB / Ensita.net <___/ www.mysql.com -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
