Women in Technology

Hear us Roar



Article:
  How to Misuse SQL's FROM Clause
Subject:   Another option?
Date:   2004-10-22 08:35:21
From:   solutions@netgis.com
Should a sub-query in the FROM clause be considered?


select a.CUSTOMER_ID, a.CUSTOMER_NAME
from CUSTOMERS a
join
(select b.CUSTOMER_ID
from ORDERS b
where b.ORDERED_DATE >= ...
group by b.CUSTOMER_ID) b
on
a.CUSTOMER_ID = b.CUSTOMER_ID
where a.ZIP_CODE in ...
order by a.CUSTOMER_NAME