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SUBQUERY or CASE STATEMENT or something

Posted on 2012-04-05
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Last Modified: 2012-04-05
I need to set a char column called COL_A to 'X'  if the sub query below returns any rows:

SELECT TYPE FROM TABLEF WHERE  ANYCOLUMN = 'Y'.

iF IT DOES NOT RETURN ANY ROWS, I NEED TO LEAVE IT THE SAME VALUE:


So what I need to do in more english terms:

Set COL_A = 'X' when exists (SELECT TYPE FROM TABLEF WHERE  ANYCOLUMN = 'Y'.)
    else do not do anything to the column.
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Question by:garyinmiami2003
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5 Comments
 
LVL 28

Expert Comment

by:sammySeltzer
ID: 37812807
Update YourTableA

set COL_A =  'X'

From tableF where tableA.ID = tableF.ID and tableF. AnyColumn ='Y' 

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Author Comment

by:garyinmiami2003
ID: 37812836
Well, this is not the solution I was hoping for.  I'm trying to update the value of a column in a Select rather than a seperate  operation.

If what you have is the way I must go, then ok.
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LVL 13

Expert Comment

by:alpmoon
ID: 37812838
If you need to update another value in case of non-existence:

update TableX
set Col_a = case when exists (SELECT TYPE FROM TABLEF WHERE  ANYCOLUMN = 'Y') then 'X' else 'Z' end
0
 

Author Comment

by:garyinmiami2003
ID: 37812854
almost there

your code: else 'Z' end

I do not want the column changed if sub query returns nothing, so could I just say else Col_a?
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LVL 13

Accepted Solution

by:
alpmoon earned 500 total points
ID: 37812861
You can do that way as well. But it is effectively the same with what sammySeltzer suggested

update TableX
from TableX
set Col_a = case when exists (SELECT TYPE FROM TABLEF WHERE  ANYCOLUMN = 'Y') then 'X' else Col_a end
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