Max value from joined table - sql

Question

I have two tables:
Operations (op_id,super,name,last)
Orders (or_id,number)
Operations:
+--------------------------------+
|op_id| super| name | last|
+--------------------------------+
|1 1 OperationXX 1 |
|2 1 OperationXY 2 |
|3 1 OperationXC 4 |
|4 1 OperationXZ 3 |
|5 2 OperationXX 1 |
|6 3 OperationXY 2 |
|7 4 OperationXC 1 |
|8 4 OperationXZ 2 |
+--------------------------------+
Orders:
+--------------+
|or_id | number|
+--------------+
|1 2UY |
|2 23X |
|3 xx2 |
|4 121 |
+--------------+
I need query to get table:
+-------------------------------------+
|or_id |number |max(last)| name |
|1 2UY 4 OperationXC|
|2 23X 1 OperationXX|
|3 xx2 2 OperationXY|
|4 121 2 OperationXZ|
+-------------------------------------+

Answer 1

use corelared subquery and join
select o.*,a.last,a.name from
(
select super,name,last from Operations from operations t
where last = (select max(last) from operations t2 where t2.super=t.super)
) a join orders o on t1.super =o.or_id
you can use row_number as well
with cte as
(
select * from
(
select * , row_number() over(partition by super order by last desc) rn
from operations
) tt where rn=1
) select o.*,cte.last,cte.name from Orders o join cte on o.or_id=cte.super

Answer 2

SELECT Orders.or_id, Orders.number, Operations.name, Operations.last AS max
FROM Orders
INNER JOIN Operations on Operations.super = Orders.or_id
GROUP BY Orders.or_id, Orders.number, Operations.name;
I don't have a way of testing this right now, but I think this is it.
Also, you didn't specify the foreign key, so the join might be wrong.