如何在SQL服务器中找到只完成一笔交易的客户ID

Question

create  table productdetails
(
    orderid int,
    Customerid varchar (100),
    orderdate date,
    productid varchar(10),
    Quality tinyint
)

insert into productdetails 
values (3, 'c2', '12-16-2020', 'p2', 2),
       (4, 'c4', '12-16-2020', 'p3', 5),
       (5, 'c2', '12-17-2020', 'p2', 1),
       (6, 'c1', '12-17-2020', 'p3', 2),
       (7, 'c3', '12-18-2020', 'p1', 5),
       (8, 'c4', '12-18-2020', 'p1', 9),
       (9, 'c5', '12-19-2020', 'p5', 8)

Answer 1

SELECT P.CustomerID
FROM PRODUCTDETAILS AS P
GROUP BY P.CustomerID
HAVING COUNT(P.orderid)=1