面试之BI-SQL--table转换[2]

month   salesPerMonth

1	2
2	3
3	2
4	4
5	3
6	3

 

写条SQL语句把上表转成下表：

month   总销量

1             2

2             5

3             7

4             11

5             14

6             17

答案：

selects2.[month],Sum(s1.salesPerMonth)as'总销量'

  FromSaless1,Saless2

  where  s1.[month]<=s2.[month]

  Groupbys2.[month]