问题
I have a table with every operations that appends before an event group by another value.
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 | + ----------+----------+-----------+------------------------+
I want to know which operations occurs before every blocking group by Rollcycle. I need to do this in access SQL.
Output
+ ----------+----------+---+---+---+ | 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 | + ----------+----------+---+---+---+
I could not find anything similar. It's maybe too specific.
Please help :)
EDIT: back to original table
回答1:
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
来源：https://stackoverflow.com/questions/59196643/finding-first-occurence-of-multiples-value-in-every-group-sort-by-date-in-sql