Efficient latest record query with Postgresql

Question

I need to do a big query, but I only want the latest records.

For a single entry I would probably do something like

SELECT * FROM table WHERE id = ?          


        

Answer 1

this could be more eficient. Difference: query for table b is executed only 1 time, your correlated subquery is executed for every row:

SELECT * 
FROM table a 
JOIN (SELECT ID, max(date) maxDate
        FROM table
      GROUP BY ID) b
ON a.ID = b.ID AND a.date = b.maxDate
WHERE ID IN $LIST