WINDOW FUNCTION SUM

description

计算窗口内数据的和

1. SUM([ALL] expression) [OVER (analytic_clause)]

example

按照 property 进行分组，在组内计算当前行以及前后各一行的x列的和。

1. select x, property,
2. sum(x) over
3. (
4. partition by property
5. order by x
6. rows between 1 preceding and 1 following
7. ) as 'moving total'
8. from int_t where property in ('odd','even');

10. | x  | property | moving total |
11. |----|----------|--------------|
12. | 2  | even     | 6            |
13. | 4  | even     | 12           |
14. | 6  | even     | 18           |
15. | 8  | even     | 24           |
16. | 10 | even     | 18           |
17. | 1  | odd      | 4            |
18. | 3  | odd      | 9            |
19. | 5  | odd      | 15           |
20. | 7  | odd      | 21           |
21. | 9  | odd      | 16           |

keywords

1. WINDOW,FUNCTION,SUM