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;
