that's the reason I used MINUS..

there is no one to one mapping between these 2 tables..

I'm just trying to delete data from Table1 which does not exist in Table2...
that's it..

I tried it did not work
my script looks like this 

(select col1 from Table1
MINUS
select concat('A_',col1) from Table2 where 
Col2 = '748' and