relative complement of two tables

[chucklarge]

Hello,
I am looking for the relative complement of two tables in MySQL. thats the term in set theory anyway,

{1,2,3} − {2,3,4} = {1}

{2,3,4} − {1,2,3} = {4}

so basically i have two tables, and i want to know the difference in one compared to the other

for example

table a

Accounting
john smith
doug brown
sony
microsoft
jeremy wright

table b

john smith
Tom sutherland
doug brown
jeremy wright
Alan Jones

and i what i need is

Accounting
sony
microsoft

Any help is appreciated,
chuck

[bogu]

If u are under mysql 4.1 :

SELECT * FROM table_a
WHERE `field` NOT IN (SELECT field FROM table_b)

on 4.0 or lower u make one select from table_b and then select all from table_a that is not in table_b ...