发生错误,我试图看出什么是错的,无济于事。请帮忙
SELECT UserId, AVG(Total) AS AvgOrderTotal
FROM Invoices
HAVING COUNT(OrderId) >= 1
1
投票
投票
你错过了GROUP BY
:
SELECT UserId, AVG(Total) AS AvgOrderTotal
FROM Invoices
GROUP BY UserId
HAVING COUNT(OrderId) >= 1
假设OrderId
永远不是NULL
,HAVING
是多余的,所以也许这就足够了:
SELECT UserId, AVG(Total) AS AvgOrderTotal
FROM Invoices
GROUP BY UserId;