Question

I have a problem getting this JPA query to work on MS SQL Server 2008.

The background is as follows: Users create jobs for clients, of which there are many. I am displaying a list of his most recently used clients to the user to make the selection easier.

SELECT DISTINCT c FROM Client c 
    JOIN c.jobs j 
    WHERE j.user = ?1 
    ORDER BY j.created DESC

The query works just fine – using MySQL. MS SQL Server (2008) complains that I cannot sort by j.created because it is not part of the select list. This is the error message:

ORDER BY items must appear in the
select list if SELECT DISTINCT is
specified.

I can’t seem to find an elegant workaround for this limitation. Does anyone have an idea?

Answer 1

Because you are selecting a distinct c from many, Sql server won’t know which j.created to order by. You can group by c and then use an aggregate to order by the min or max j.created. Something like…

SELECT c.col1, c.col2 
FROM Client c 
JOIN c.jobs j 
WHERE j.user = ?1 
Group by c.col1, c.col2
ORDER BY MIN(j.created) DESC