> I have 2 tables with table A containing an 'email' field and table B[color=blue]
> containing 2 fields 'primaryemail' and 'secondaryemail'. Now is it possible
> to issue a query that would return only the unqiue email addresses in these
> 3 fields? So a long list with no duplicate emails(distinct).[/color]
Depends on the version of MySQL you are using. If you are using 4.1
review the manual section on subqueries, particularly this section:
http://www.mysql.com/documentation/m...STS_subqueries
Example: What kind of store is present in all cities?
SELECT DISTINCT store_type FROM Stores S1
WHERE NOT EXISTS (
SELECT * FROM Cities WHERE NOT EXISTS (
SELECT * FROM Cities_Stores
WHERE Cities_Stores.city = Cities.city
AND Cities_Stores.store_type = Stores.store_type));
If you're not using 4.1, then you won't be able to do it in a single
query. Give more information about the version you are using, and I'll
try to help.
Lukas
