Question

I have a function that I need to create that reads in the value of a column in a table and output a text value into a new column in the same table. The column in question (confidence_score) will have either a numeric value, a letter, or null value.

If confidence_score(nvarchar(2)) is a number and is less than or equal to 14, I need the computed column to have ‘High’ in it, otherwise ‘Low’. If confidence_score is not a number and has a value of ‘H’, I need the computed column to have ‘High’ in it, otherwise ‘Low’.

Here is the code I am using:

CREATE FUNCTION dbo.avm_confidence_level(@score nvarchar)
RETURNS nvarchar(5) as
BEGIN
DECLARE @conversion as nvarchar(5)
    IF isnumeric(@score) = 1 BEGIN
        IF cast(@score as int) <= 14 BEGIN
            Set @conversion = 'High'
        END
        ELSE BEGIN
            Set @conversion = 'Low'
        END
    END
    ELSE BEGIN
        IF @score = 'H' BEGIN
            Set @conversion = 'High'
        END
        ELSE BEGIN
            Set @conversion = 'Low'
        END
    END

    RETURN @conversion
END

I am getting results using this code that are half right. The first check (isnumeric) seems to be working fine. I am getting High and Low values where I’m expecting them when the value is not a number. The issue seems to be within the isnumeric being true section. I am getting a value of ‘High’ regardless of what numeric value is actually in the confidence_score column. I’m not sure what I’m doing wrong here.

I appreciate any help anyone can offer.

Thank you.

Answer 1

It’s because you defined the function parameter as nvarchar instead of nvarchar(2). It’s truncating anything over one character, so all your ints above 9 are becoming 1. Try changing the definition to:

CREATE FUNCTION dbo.avm_confidence_level(@score nvarchar(2))