--试试看DECLARE @AVG FLOATSELECT @AVG=AVG(TOTAL)FROM (
SELECT C.客户编号,
SUM(B.销售单价*C.销售数量) TOTAL
FROM 产品信息 B, 销售信息 C
WHERE B.产品编号=C.产品编号
GROUP BY C.客户编号
) TSELECT COUNT(*) FROM (
SELECT C.客户编号,
CASE WHEN
SUM(B.销售单价*C.销售数量)> @AVG THEN SUM(B.销售单价*C.销售数量)
ELSE NULL
...
