Question

I have a table that look like that

projectID , year , jan , feb , mar , apr , may ....  

each one reprsent a numeric coulm
and I want to get the value at a specific colums that determine by a value that sended to the function.

I Have this Function

CREATE FUNCTION [dbo].[func_] 
(   @BRANCH_ID      NUMERIC(6,0) = 0,   
    @JOB_TYPE_ID    NUMERIC(6,0) = 0,   
    @PROJECT_ID     NUMERIC(6,0) = 0,
    @MONTH_NAME     varchar(10) = 0,    
    @YEAR_NUMBER    NUMERIC(6,0) = 0)
RETURNS NUMERIC(6,1)
AS
BEGIN
    DECLARE @FORCAST NUMERIC(6,1)

    SELECT  @FORCAST =   @MONTH_NAME
    FROM    TABLE
    WHERE   Projectid = @PROJECT_ID                                 
            AND Year = @YEAR_NUMBER

    IF @FORCAST IS NULL
        RETURN(0)

    RETURN(@FORCAST)
END

For example if I execute the function today and send the year and month of today it will return the value in “mar” column.

Answer 1

You could use UNPIVOT if it’s available in your version of SQL Server (it’s available starting from SQL Server 2005):

SELECT @FORCAST = Forecast
FROM [TABLE] t
UNPIVOT (
  Forecast FOR Month IN (jan, feb, mar, ...)
) u
WHERE Projectid = @PROJECT_ID
  AND Year      = @YEAR_NUMBER
  AND Month     = LEFT(@MONTH_NAME, 3)

Otherwise it could be something like this:

SELECT
  @FORCAST = CASE @MONTH_NAME
    WHEN 'January'  THEN jan
    WHEN 'February' THEN feb
    WHEN 'March'    THEN mar
    ...
  END
FROM [TABLE]
WHERE Projectid = @PROJECT_ID
  AND Year      = @YEAR_NUMBER