Re: How to exclude the result of union of two tables from the result of union of other two tables

Oz wrote:

I have a php page where I would like to list a numer of companies as below: 1- retrieve all distinct company names from TableA (SELECT company_name FROM TableA)

CREATE TEMPORARY TABLE temp1 SELECT DISTINCT(company_name) FROM TableA

2- retrieve all distinct company names from TableB 3- combine the two lists as list1

INSERT INTO temp1 SELECT DISTINCT(company_name) FROM TableB

4- retrieve all distinct company names from TableC

CREATE TEMPORARY TABLE temp2 SELECT DISTINCT(company_name) FROM TableC

5- retrieve all distinct company names from TableD 6- combine the two lists as list2

INSERT INTO temp2 SELECT DISTINCT(company_name) FROM TableD

7- display company names in list1 that don't exist in list2

SELECT t1.company_name FROM temp1 t1 LEFT JOIN temp2 t2 ON t1.company_name = t2.company_name WHERE t2.company_name IS NULL

MySql version is 3.23.56 3.23.56 , so I cannot use UNION. I would like to accomplish this with as little php code as possible, using mostly SQL.

How about using all SQL? :) All of this is in the MySQL manual, btw... -- ---John Holmes... Amazon Wishlist: www.amazon.com/o/registry/3BEXC84AB3A5E/ php|architect: The Magazine for PHP Professionals – www.phparch.com