how to get distinct values from second table on comparing with first table

Article:		SQL Subqueries
Subject:		how to get distinct values from second table on comparing with first table
Date:		2008-04-02 23:40:27
From:		senthil.N

I'm having 2 tables as shown below tb1 tb2 col1 col2 col1 col2 10 10000 10 10000 11 15000 15 20000 15 20000 13 21000 21 21000 23 10000 i need solution like this col1 col2 10 10000 11 15000 21 21000 13 21000 23 10000 plz help me !