ID ArrivalPort DeparturePort 1 A B 1 A C 2 A B 2 C D
如何对这两种情况进行唯一/不同的计数 ArrivalPort 和 DeparturePort 通过 ID ?
ArrivalPort
DeparturePort
ID
Out ID Count 1 3 2 4
谢谢
可以在派生表中进行并集,然后进行计数:
select ID, count(distinct Port) as Count from (select id, ArrivalPort as Port from table_name union all select id, DeparturePort from table_name) t group by id;
Fiddle
