Thanks. I added orders.order_date to the list of fields being
selected, but it still returns "invalid use of group function".
On Nov 3, 2009, at 1:09 PM, Martin Gainty wrote:
> any column used in any group functions such as SUM needs to be
> requested in select column e.g.
> select foo from table where sum(foo)=1.00
>> select * from customers
>> left join orders on customers.cust_id = orders.cust_id
>> where signup_date < now() - interval 14 day
>> and sum(if(order_date > now() - interval 14 day, 1, 0)) = 0
>> But that gives me "Invalid use of group function".