data1
id | date | value |
1 | 2000/12/3 | |
1 | 2000/12/5 | 6 |
1 | 2000/12/8 | 7 |
2 | 2000/12/4 | |
2 | 2000/12/6 | 2 |
3 | 2000/12/3 | 4 |
3 | 2000/12/7 | 5 |
3 | 2000/12/9 | 7 |
data2
id | date |
1 | 2000/12/1 |
1 | 2000/12/2 |
1 | 2000/12/3 |
1 | 2000/12/4 |
1 | 2000/12/5 |
1 | 2000/12/6 |
1 | 2000/12/7 |
1 | 2000/12/8 |
1 | 2000/12/9 |
1 | 2000/12/10 |
2 | 2000/12/1 |
2 | 2000/12/2 |
2 | 2000/12/3 |
2 | 2000/12/4 |
2 | 2000/12/5 |
2 | 2000/12/6 |
2 | 2000/12/7 |
2 | 2000/12/8 |
2 | 2000/12/9 |
2 | 2000/12/10 |
3 | 2000/12/1 |
3 | 2000/12/2 |
3 | 2000/12/3 |
3 | 2000/12/4 |
3 | 2000/12/5 |
3 | 2000/12/6 |
3 | 2000/12/7 |
3 | 2000/12/8 |
3 | 2000/12/9 |
3 | 2000/12/10 |
请问有没有办法合并出下面的结果,在第一项数值出现之前,value一项全部填零,在第一个数值出现之後,value一项一直填那个数字,直到更新为止。用merge, sql等什麽方法都没有所谓。感激不尽!!!!!
result
id | date | value |
1 | 2000/12/1 | 0 |
1 | 2000/12/2 | 0 |
1 | 2000/12/3 | 0 |
1 | 2000/12/4 | 0 |
1 | 2000/12/5 | 0 |
1 | 2000/12/6 | 6 |
1 | 2000/12/7 | 6 |
1 | 2000/12/8 | 7 |
1 | 2000/12/9 | 7 |
1 | 2000/12/10 | 7 |
2 | 2000/12/1 | 0 |
2 | 2000/12/2 | 0 |
2 | 2000/12/3 | 0 |
2 | 2000/12/4 | 0 |
2 | 2000/12/5 | 0 |
2 | 2000/12/6 | 2 |
2 | 2000/12/7 | 2 |
2 | 2000/12/8 | 2 |
2 | 2000/12/9 | 2 |
2 | 2000/12/10 | 2 |
3 | 2000/12/1 | 0 |
3 | 2000/12/2 | 0 |
3 | 2000/12/3 | 4 |
3 | 2000/12/4 | 4 |
3 | 2000/12/5 | 4 |
3 | 2000/12/6 | 4 |
3 | 2000/12/7 | 5 |
3 | 2000/12/8 | 5 |
3 | 2000/12/9 | 7 |
3 | 2000/12/10 | 7 |