相关子查询在Netezza中不起作用

Question

我在Netezza中有一个这样的查询，但不确定如何重写它才能工作。感谢

with dates as (
select distinct event_date from table
)
select event_date, 
(select count(distinct id)
from table 
where event_date < dates.event_date
)
from dates

This form of correlated query is not supported - consider rewriting

Answer 1

无论如何，使用窗口函数会更高效。我认为逻辑是：

select event_date, 
sum(count(*)) over (order by event_date) - count(*) as events_before
from table
group by event_date