Select max date before min date in another table - sql

Question

I have three tables.
Order_Status
Order_ID order_status_id Timestamp
1 2 12/24/19 0:00
1 3 12/24/19 0:10
1 4 12/24/19 0:30
1 5 12/24/19 1:00
2 2 12/24/19 15:00
2 3 12/24/19 15:07
2 9 12/24/19 15:10
2 8 12/24/19 15:33
2 10 12/24/19 16:00
4 4 12/24/19 19:00
4 2 12/24/19 19:30
4 3 12/24/19 19:32
4 4 12/24/19 19:40
4 5 12/24/19 19:45
5 2 1/28/19 19:30
5 6 1/28/19 19:48
Contact
Order_id Contact_time
1 12/24/19 0:25
2 12/24/19 15:30
4 12/24/19 19:38
5 1/28/19 19:46
meta_status
order_status_id status_description
1 desc1
2 desc2
3 desc3
4 desc4
5 desc5
I am trying to retrieve the max order Timestamp before min Contact Time. I need it to be group by orderID, I also need the order_status_id and the status_description
This is my query so far
SELECT a.Order_ID,
a.order_status_id,
c.status_description,
MAX(CASE
WHEN a.order_timestamp < b.Contact_Time then
a.order_timestamp
ELSE
null
END) AS beforeContact
FROM Order_Status a
LEFT JOIN Contact b
ON b.Order_ID = a.Order_ID
LEFT JOIN meta_status c
ON c.order_status_id = a.order_status_id
GROUP BY a.Order_ID, a.order_status_id, c.status_description
But it still returns every row in the tables. I need it to be only 4 rows which represent 4 orders 1,2,4,5 and the max order timestamp before contact time.
Do I need to use subquery or windowing function for this?

Answer 1

This is it:
select a.* from (SELECT a.ordertimestamp,
a.order_status_id,
c.status_description,
a.order_timestamp AS beforeContact,
rank() over (partition by a.Order_ID order by a.order_timestamp desc) as
rank1
FROM Order_Status a
LEFT JOIN Contact b
ON b.Order_ID = a.Order_ID
LEFT JOIN meta_status c
ON c.order_status_id = a.order_status_id
where a.order_timestamp < b.Contact_Time
GROUP BY a.Order_ID, a.order_status_id, c.status_description)as a
where rank1=1;