Question

I have a function that takes 2 parameters: @iEmployeeID and @dDate.

It’s purpose is to find a budget rate for the given parameters. In other words, it should find the largest date being smaller or equal to the @dDate argument, and return the rate that corresponds.

Budget rates are:

Start        Rate
-------      -----
01-01-2008   600
01-01-2009   800
01-01-2010   700

DECLARE @result decimal(38,20)

SELECT @result = decRate
FROM BudgetRates BR
WHERE BR.iRefEmployeeID = @iEmployeeID
GROUP BY decRate
HAVING MAX(BR.dStart) <= @dDate

RETURN @result

• When supplied the argument 06-06-2008, it correctly returns 600.
• When supplied the argument 03-03-2009, it correctly returns 800
• When supplied the argument 02-02-2010, it should return 700. The function actually returns 800.

Where is the bug?

bug hunting:
If I tweak around with the figures, it seems to pick the largest rate if it has 2 values to pick from.

Answer 1

Surely your code shouldn’t be grouping at all?

SELECT TOP 1 @result = decRate
FROM BudgetRates BR
WHERE BR.iRefEmployeeID = @iEmployeeID
AND BR.dStart <= @dDate
ORDER BY BR.dStart DESC

RETURN @result