Question

I have an employee table and a leave_allocation table which has a one-to-many relationship, Each employee has a number of leave allocations over a period of time. I would like to get the LATEST allocation for each employee.

I tried the query but the date and the days values do not correlate to the same row

select e.employee_number, e.nme, MAX(l.date), l.days 
from employee e, leave_allocation l 
where l.employee_id = e.employee_id
group by e.employee_number, e.nme

How can I get the latest allocation per employee?

Answer 1

Place the MAX() date in a subquery:

SELECT e.employee_number, e.nme, l.leavedate, la.days
FROM employee e
INNER JOIN
(
   SELECT Max(date) leavedate, employee_id
   FROM leave_allocation
   GROUP BY employee_id
) l
   ON e.employee_id = l.employee_id
INNER JOIN leave_allocation la
   ON l.employee_id = la.employee_id
   AND l.leavedate = la.date

I also switched the query to use ANSI join syntax instead of commas between the tables.