这们写你试一下
SELECT P.ProductName,P.Specif,SUM(S.Scalar) Scalar,
(CASE month(dateT) WHEN 1 THEN SUM(S.Scalar) ELSE 0 END) '1月',
(CASE month(dateT) WHEN 2 THEN SUM(S.Scalar) ELSE 0 END) '2月',
(CASE month(dateT) WHEN 3 THEN SUM(S.Scalar) ELSE 0 END) '3月',
(CASE month(dateT) WHEN 4 THEN SUM(S.Scalar) ELSE 0 END) '4月',
(CASE month(dateT) WHEN 5 THEN SUM(S.Scalar) ELSE 0 END) '5月',
(CASE month(dateT) WHEN 6 THEN SUM(S.Scalar) ELSE 0 END) '6月',
(CASE month(dateT) WHEN 7 THEN SUM(S.Scalar) ELSE 0 END) '7月'
FROM product P LEFT OUTER JOIN Sell S
ON P.ID=S.ProdID
GROUP BY P.ProductName,P.Specif,Month(DateT)