BigQuery 中的数据透视表

Question

如何在 BigQuery 中进行数据透视？

假设我的桌子是这样的 -

id   event 
----------
1    type 1    
1    type 2    
2    type 2    
2    type 2    
2    type 2     
3    type 1

我想查询这样的东西 -

id type1 type2
----------
1   1    1     
2   0    3
3   1    0

Answer 1

您可以使用条件聚合：

select id,
       sum(case when event = 'type 1' then 1 else 0 end) as type1,
       sum(case when event = 'type 2' then 1 else 0 end) as type2
from t
group by id;

Answer 2

你需要有条件的sum()

select id, sum(case when event = 'type 1' then 1 else 0 end) as type1,
           sum(case when event = 'type 2' then 1 else 0 end) as type2
from table t
group by id;