SQL Query with LEFT JOIN Issue

Question

I am having problems with a left join SQL query but can\'t see why it isn\'t working. I have 3 tables: customers, purchases and payments, and i\'m trying to select customers who

Answer 1

Unfortunately you can't reference an alias on the same "level" where it's defined.

You need to wrap everything into a derived table:

select *
from (
   
) t
where balance > 0