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DB2 sql: where clausole : something OR (table is empty)

Posted on 2011-03-08
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Last Modified: 2012-05-11
HI,
I would like to have
a condition where in which I test if an element is present
in a tableX OR the tableX is empty.
The where will return true if the element is present in tableX
BUT return true even if the tableX is empty.
How do I do?
thanks
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Question by:bobdylan75
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5 Comments
 

Author Comment

by:bobdylan75
ID: 35069487
select * from tableA
where tableA.key in (select key from tableX) OR tableX is empty...

Is there a way like that..
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Accepted Solution

by:
Kent Olsen earned 500 total points
ID: 35069551

Hi Bob,

SELECT * FROM tableA
WHERE tableA.key in (select key from tableX)
  OR ((Select count(*) from tablex) = 0)


Will that work?


Kent
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LVL 3

Expert Comment

by:CarlsbergFTW
ID: 35069646
Try using an outer join against the table that might have null or no value ?
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Author Comment

by:bobdylan75
ID: 35070181
Thank you CarlsbergFTW,
but I think the easy way is that one of Kdo.
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Author Closing Comment

by:bobdylan75
ID: 35070184
thank you!
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