GROUP BY having MAX date

Question

I have problem when executing this code:

SELECT * FROM tblpm n 
WHERE date_updated=(SELECT MAX(date_updated) 
FROM tblpm GROUP BY control_number 
HAVING cont         


        

Answer 1

Fast and easy with HAVING:

SELECT * FROM tblpm n 
FROM tblpm GROUP BY control_number 
HAVING date_updated=MAX(date_updated);

In the context of HAVING, MAX finds the max of each group. Only the latest entry in each group will satisfy date_updated=max(date_updated). If there's a tie for latest within a group, both will pass the HAVING filter, but GROUP BY means that only one will appear in the returned table.