I wrote this query to show me the last purchase of each customers using “EXISTS” but it is not working. it returns all of the rows without filtering them. Can you please advise me how to resolve this issue?
Thank you in advance

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SELECT O1.custid, O1.orderid, O1.orderdate, O1.empid 
FROM Sales.Orders AS O1
WHERE EXISTS             (
                SELECT O2.custid, MAX(O2.orderdate)
                FROM Sales.Orders AS O2
                WHERE O2.custid=O1.custid 
                GROUP BY O2.custid
             );