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CASE STATEMENT RETURNING NULLS

I am writing this function and when i call it with a select statement I am getting nulls. Any ideas?

ALTER FUNCTION [dbo].[fn_deductible]
(
      -- Add the parameters for the function here
            @DEDUCTIBLEAMT VARCHAR(7)
)
RETURNS varchar (1)
AS
BEGIN
-- Declare the return variable here

DECLARE @DEDUCTIBLE varchar(1)
DECLARE @DEDUCTIBLETEMP varchar(7)


-- Add the T-SQL statements to compute the return value here

SET @DEDUCTIBLETEMP = CAST(@DEDUCTIBLEAMT AS NUMERIC (7,0))
set @DEDUCTIBLE = case @DEDUCTIBLETEMP


when '> 100 and <= 250' then '4'
when  '> 500 and  <= 750' then '6'
when  '> 750 and  <= 1000' then '7'
when  '> 1000 and  <= 2500' then '8'
when  '> 2500 and  <= 5000' then '9'
when  '> 5000 and  <= 10000' then 'A'
when  '> 10000 and  <= 25000' then 'B'
when  '> 25000 and  <= 50000' then 'C'
when  '> 50000 and  <= 75000' then 'D'
when  '> 75000 and  <= 100000' then 'E'
when  '> 100000 and  <= 200000' then 'F'
when  '> 200000 and  <= 250000' then 'G'
when  '> 250000 and  <= 300000' then 'H'
when  '> 300000 and  <= 400000' then 'I'
when  '> 400000 and  <= 500000' then 'J'
when  '> 500000' then 'k'
end

      RETURN @DEDUCTIBLE

END
Avatar of CCongdon
CCongdon
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Is it possible that DEDUCTUIBLETEMP is coming out with a valuie less than or equal to 100? That would give you a NULL result.

Try adding ELSE '!!' after when  '> 500000' then 'k' and see if you get any !! in your results. If so, then you are getting some values less than 101 OR you are getting NULL values as inputs.
Sorry make that a single exclamation point. I just noticed that your sp returns a single character.
Avatar of Guy Hengel [angelIII / a3]
this should do it.
ALTER FUNCTION [dbo].[fn_deductible] 
(
      -- Add the parameters for the function here
      @DEDUCTIBLEAMT VARCHAR(7)
)
RETURNS varchar (1)
AS
BEGIN
-- Declare the return variable here 
DECLARE @DEDUCTIBLE varchar(1)
DECLARE @DEDUCTIBLETEMP NUMERIC (7,0) 

-- Add the T-SQL statements to compute the return value here 
SET @DEDUCTIBLETEMP = CAST(@DEDUCTIBLEAMT AS NUMERIC (7,0))
set @DEDUCTIBLE = case 
when @DEDUCTIBLETEMP > 100 and @DEDUCTIBLETEMP <= 250 then '4'
when @DEDUCTIBLETEMP > 500 and @DEDUCTIBLETEMP <= 750 then '6'
when @DEDUCTIBLETEMP > 750 and @DEDUCTIBLETEMP <= 1000 then '7'
when @DEDUCTIBLETEMP > 1000 and @DEDUCTIBLETEMP <= 2500 then '8'
when @DEDUCTIBLETEMP > 2500 and @DEDUCTIBLETEMP <= 5000 then '9'
when @DEDUCTIBLETEMP  > 5000 and @DEDUCTIBLETEMP  <= 10000 then 'A'
when @DEDUCTIBLETEMP  > 10000 and  @DEDUCTIBLETEMP <= 25000 then 'B'
when @DEDUCTIBLETEMP  > 25000 and  @DEDUCTIBLETEMP <= 50000 then 'C'
when @DEDUCTIBLETEMP  > 50000 and  @DEDUCTIBLETEMP <= 75000 then 'D'
when @DEDUCTIBLETEMP  > 75000 and  @DEDUCTIBLETEMP <= 100000 then 'E'
when @DEDUCTIBLETEMP  > 100000 and @DEDUCTIBLETEMP  <= 200000 then 'F'
when  @DEDUCTIBLETEMP > 200000 and @DEDUCTIBLETEMP  <= 250000 then 'G'
when  @DEDUCTIBLETEMP > 250000 and  @DEDUCTIBLETEMP <= 300000 then 'H'
when  @DEDUCTIBLETEMP > 300000 and  @DEDUCTIBLETEMP <= 400000 then 'I'
when  @DEDUCTIBLETEMP > 400000 and  @DEDUCTIBLETEMP <= 500000 then 'J'
when  @DEDUCTIBLETEMP > 500000 then 'k'
end 
      RETURN @DEDUCTIBLE 
END

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Avatar of jtsoos
jtsoos

ASKER

this is what wound up working

ALTER FUNCTION [dbo].[fn_deductible2]
(
      -- Add the parameters for the function here
      @DEDUCTIBLEAMT VARCHAR(7)
)
RETURNS varchar (1)
AS
BEGIN
      -- Declare the return variable here
      DECLARE @DEDUCTIBLECODE varchar(1)


      -- Add the T-SQL statements to compute the return value here
select @DeductibleCode = CASE

WHEN cast(@DeductibleAmt as int) BETWEEN 0 AND 50 THEN '2'
WHEN cast(@DeductibleAmt as int) BETWEEN 51 AND 100 THEN '3'
WHEN cast(@DeductibleAmt as int) BETWEEN 101 AND 250 THEN '4'
WHEN cast(@DeductibleAmt as int) BETWEEN 251 AND 500 THEN '5'
WHEN cast(@DeductibleAmt as int) BETWEEN 501 AND 750 THEN '6'
WHEN cast(@DeductibleAmt as int) BETWEEN 751 AND 1000 THEN '7'
WHEN cast(@DeductibleAmt as int) BETWEEN 1001 AND 2500 THEN '8'
WHEN cast(@DeductibleAmt as int) BETWEEN 2501 AND 5000 THEN '9'
WHEN cast(@DeductibleAmt as int) BETWEEN 5001 AND 10000 THEN 'A'
WHEN cast(@DeductibleAmt as int) BETWEEN 10001 AND 25000 THEN 'B'
WHEN cast(@DeductibleAmt as int) BETWEEN 25001 AND 50000 THEN 'C'
WHEN cast(@DeductibleAmt as int) BETWEEN 50001 AND 75000 THEN 'D'
WHEN cast(@DeductibleAmt as int) BETWEEN 75001 AND 100000 THEN 'E'
WHEN cast(@DeductibleAmt as int) BETWEEN 100001 AND 200000 THEN 'F'
WHEN cast(@DeductibleAmt as int) BETWEEN 200001 AND 250000 THEN 'G'
WHEN cast(@DeductibleAmt as int) BETWEEN 250001 AND 300000 THEN 'H'
WHEN cast(@DeductibleAmt as int) BETWEEN 300001 AND 400000 THEN 'I'
WHEN cast(@DeductibleAmt as int) BETWEEN 400001 AND 500000 THEN 'J'
WHEN CAST(@DEDUCTIBLEAMT AS INT) > 500000 THEN 'K'

ELSE '99'

END


      -- Return the result of the function
      RETURN @DEDUCTIBLECODE

END
well...

ELSE '99'

is incompatible with

RETURNS varchar (1)


you need to change to

RETURNS varchar (2)
another question:
why is your function parameter data types varchar(7) and not INT directly?
I would propose something much simpler and faster, if you give me 2 minutes
The gains:

Casting is done only once

Testing does not have to revisit the "BETWEEN 2" conditions. Remember that CASE takes only the first match.

Nulls and -ve (the only two cases caught by ELSE) are now handled as X

Yes, Angel is right. Your ELSE '99'  will cause '9' to be returned, and it will confuse the hell out of you!  (same as 2501-5000)

Your boundary condition

WHEN cast(@DeductibleAmt as int) BETWEEN 400001 AND 500000 THEN 'J'
WHEN CAST(@DEDUCTIBLEAMT AS INT) > 500000 THEN 'K'

Misses when it's 500000 exactly.
ALTER FUNCTION [dbo].[fn_deductible2]
(
      -- Add the parameters for the function here
      @DEDUCTIBLEAMT VARCHAR(7)
)
RETURNS varchar (1)
AS
BEGIN
 
-- Declare the return variable here
DECLARE @DEDUCTIBLECODE varchar(1)
DECLARE @DeductibleAmtINT int
SET @DeductibleAmtINT = IsNull(Cast(@DeductibleAmt as Int), -1)
 
-- Add the T-SQL statements to compute the return value here
select @DeductibleCode = CASE
WHEN @DeductibleAmtInt < 0 THEN 'X'
WHEN @DeductibleAmtInt < 50 THEN '2'
WHEN @DeductibleAmtInt < 100 THEN '3'
WHEN @DeductibleAmtInt < 250 THEN '4'
WHEN @DeductibleAmtInt < 500 THEN '5'
WHEN @DeductibleAmtInt < 750 THEN '6'
WHEN @DeductibleAmtInt < 1000 THEN '7'
WHEN @DeductibleAmtInt < 2500 THEN '8'
WHEN @DeductibleAmtInt < 5000 THEN '9'
WHEN @DeductibleAmtInt < 10000 THEN 'A'
WHEN @DeductibleAmtInt < 25000 THEN 'B'
WHEN @DeductibleAmtInt < 50000 THEN 'C'
WHEN @DeductibleAmtInt < 75000 THEN 'D'
WHEN @DeductibleAmtInt < 100000 THEN 'E'
WHEN @DeductibleAmtInt < 200000 THEN 'F'
WHEN @DeductibleAmtInt < 250000 THEN 'G'
WHEN @DeductibleAmtInt < 300000 THEN 'H'
WHEN @DeductibleAmtInt < 400000 THEN 'I'
WHEN @DeductibleAmtInt < 500000 THEN 'J'
ELSE 'K'
END
 
-- Return the result of the function
RETURN @DEDUCTIBLECODE
 
END

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ASKER CERTIFIED SOLUTION
Avatar of Guy Hengel [angelIII / a3]
Guy Hengel [angelIII / a3]
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good point. my eyes are probably seeing BETWEEN A AND B but fried brain is thinking >A and <B ...
I have to disagree with that recommendation.

the question code reads like this:
 case @DEDUCTIBLETEMP when '> 100 and <= 250' then '4'

so, the variable was compared litterally with the string '> 100 and <= 250'
which cannot match on any of the lines.

altough the remark about the check " <= 100 " was missing in the list, that was not main problem, but the syntax problem that the code had to read instead like this:

case when @DEDUCTIBLETEMP  > 100 and  @DEDUCTIBLETEMP  <= 250 then '4'


to back up that, see:
https://www.experts-exchange.com/questions/23003599/CASE-STATEMENT-RETURNING-NULLS.html?anchorAnswerId=20414568#a20414568
this is what wound up working ... <...>

after which the questioner did not show up again.

so, if you want to give points to a single expert, that would be me...
however, I would like to recommend a point split between CCongdon , imitchie and myself.
both experts have added valuable ideas to this question
Give all the points to angel.
angel - You are correct.  I mistakenlyassumed the code was working with th eproblem being solved by the else.  The code wasn't working because the ' ' around the conditions.

mlmcc
Yes, please gives points to Angelll and not me. I simply made a quick 'grasping at straws' idea just to give the questioner something to try. Angelll certainly did more work on this question than I have.
Forced accept.

Computer101
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