SQL Server: how to add case statement to select

Question

I am using the following select to query a date from a database table.

The input (ms) for this query results from an xml string and the stored procedure then loops through all the single values in the xml to return a certain number (integer) for each of them. This works fine so far.

Is there a way that I can return a placeholder number (like 99999) if the input (ms) is empty / nothing ? Currently the below returns 0 in such a case which I cannot use to identify this as 0 can also be a valid result in other cases.

My stored procedure so far:

SELECT ms as date,
    type, 
    (
        SELECT COUNT(calendar_dt)
        FROM        Calendar
        WHERE       day_of_week NOT IN (1, 7)
        AND         calendar_dt > GETDATE()
        AND         calendar_dt <= ms
    ) as bDays
FROM @dates
FOR XML PATH('ms'), ELEMENTS, TYPE, ROOT('ranks')

Many thanks in advance for any help with this, Tim.

Answer 1

If the column "ms" is actually NULL or populated, just use ISNULL.

http://technet.microsoft.com/en-us/library/ms184325.aspx

SELECT ISNULL(ms, 99999) AS date

However, if that column can contain an empty string, which is not the same as NULL, then also use NULLIF.

http://technet.microsoft.com/en-us/library/ms177562.aspx

SELECT ISNULL(NULLIF(ms,''), 99999) AS date