在SQL中按日期排序在每个组中查找多次出现值的首次出现

问题描述

我有一个表，其中的每个操作都在事件组之前附加另一个值.

I have a table with every operations that appends before an event group by another value.

只有3种操作:R，E，P

There is only 3 operations: R, E, P

+ ----------+----------+-----------+------------------------+
| Rollcycle | Blocking | Operation | Order                  |
+ ----------+----------+-----------+------------------------+
| 1         | 3        | R         | 4                      |
| 1         | 3        | P         | 3                      |
| 1         | 3        | E         | 2                      |
| 1         | 3        | R         | 1                      |
| 1         | 2        | P         | 3                      |
| 1         | 2        | E         | 2                      |
| 1         | 2        | R         | 1                      |
| 1         | 1        | R         | 1                      |
| 2         | 1        | E         | 2                      |
| 2         | 1        | R         | 1                      |
+ ----------+----------+-----------+------------------------+

我想知道在Rollcycle的每个阻止组之前发生了哪些操作.我需要在Access SQL中执行此操作.

I want to know which operations occurs before every blocking group by Rollcycle.I need to do this in access SQL.

输出

+ ----------+----------+---+---+---+
| Rollcycle | Blocking | R | E | P |
+ ----------+----------+---+---+---+
| 1         | 1        | 1 | 0 | 0 |
| 1         | 2        | 0 | 1 | 1 |
| 1         | 3        | 1 | 0 | 0 |
| 2         | 1        | 1 | 1 | 0 |
+ ----------+----------+---+---+---+

我找不到类似的东西.可能太具体了.

I could not find anything similar. It's maybe too specific.

请帮助:)

返回原始表

推荐答案

如果我正确地跟随了您，则可以过滤order大于或等于blocking的记录，然后进行条件聚合:

If I followed you correctly, you can filter on records where order is greater or equal than blocking, and then do conditional aggregation:

select
    rollcycle,
    blocking,
    max(iif(operation = 'R', 1, 0)) R,
    max(iif(operation = 'E', 1, 0)) E,
    max(iif(operation = 'P', 1, 0)) P
from mytable 
where order >= blocking
group by rollcycle, blocking

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