主题：写在数据库的视图sql compute语句，可以有条件地求平均值吗？

额

SELECT
dbo.[每日销售].[日期],
Avg(销售额)

FROM
dbo.[每日销售]
GROUP BY
dbo.[每日销售].[日期],
dbo.[每日销售].[销售额]

Where  辅助列 >=  " & dr("辅助列")-6 & "  And 辅助列 <= " & dr("辅助列")

SELECT
dbo.[每日销售].[日期],
Avg(销售额)

FROM
dbo.[每日销售]
GROUP BY
dbo.[每日销售].[日期],
dbo.[每日销售].[销售额]

Where  辅助列 >=  1  And 辅助列 <= 10

SELECT
[日期],
(Select Avg(销售额) from  dbo.[每日销售] b Where a.日期 = b.日期 and b.辅助列 >= a.辅助列 - 6 and b.辅助列 <= a.辅助列) as Max7

FROM
dbo.[每日销售] a
GROUP BY
[日期],
[辅助列],

[销售额]

为什么不直接根据日期算。

SELECT
[日期],
(Select Avg(销售额) from  dbo.[每日销售] b Where b.辅助列 >= a.辅助列 - 6 and b.辅助列 <= a.辅助列) as Max7

FROM
dbo.[每日销售] a
GROUP BY
[日期],
[辅助列],

[销售额]