Question

I am trying to order by date. I want the most recent dates coming in first. That’s easy enough, but there are many records that are null and those come before any records that have a date.

I have tried a few things with no success:

ORDER BY ISNULL(Next_Contact_Date, 0)

ORDER BY ISNULL(Next_Contact_Date, 999999999)

ORDER BY coalesce(Next_Contact_Date, 99/99/9999)

How can I order by date and have the nulls come in last? The data type is smalldatetime.

Answer 1

smalldatetime has range up to June 6, 2079 so you can use

ORDER BY ISNULL(Next_Contact_Date, '2079-06-05T23:59:00')

If no legitimate records will have that date.

If this is not an assumption you fancy relying on a more robust option is sorting on two columns.

ORDER BY CASE WHEN Next_Contact_Date IS NULL THEN 1 ELSE 0 END, Next_Contact_Date

Both of the above suggestions are not able to use an index to avoid a sort however and give similar looking plans.

One other possibility if such an index exists is

SELECT 1 AS Grp, Next_Contact_Date 
FROM T 
WHERE Next_Contact_Date IS NOT NULL
UNION ALL
SELECT 2 AS Grp, Next_Contact_Date 
FROM T 
WHERE Next_Contact_Date IS NULL
ORDER BY Grp, Next_Contact_Date