Re: Yet another SQL newbie question

You mean like:
select * from jhhl1
....+....1...
MYKEY  MYCHAR
  A    Test A
  B    Test B
  C    Test C
********  End

Select * from jhhl2
....+....1...
MYKEY  MYCHAR
  D    Test D
  E    Test E
  F    Test F
********  End

Select * from jhhl3
....+....1....+..
MYKEY  MYCHAR 
  C    Test 1 
  F    Test 2 
********  End

select * from jhhl1
union 
select * from jhhl2
....+....1...
MYKEY  MYCHAR
  A    Test A
  B    Test B
  C    Test C
  D    Test D
  E    Test E
  F    Test F
********  End

select * from jhhl1 a 
 where a.mykey not in (select mykey from jhhl3)
union 
select * from jhhl2 b 
 where b.mykey not in (select mykey from jhhl3)
....+....1...
MYKEY  MYCHAR
  A    Test A
  B    Test B
  D    Test D
  E    Test E
********  End

In theory an EXCEPT might run more efficiently if you can set it up to run 
against the result of the union as a whole and not have to run the "not 
in" repeatedly.


Rob Berendt