在查询中基于一个 select 的两个选择

Question

Can I do one select and then do different selects on the result in one query?

Now I want to do something like that (which is not working)

select 
    (select count(*), sum(amount) from view where amount > 5), 
    (select count(*), sum(amount) from view where amount < 5) 
from 
    (select id, amount from warehouse where createDate = '2019-01-01') as view;

I don't want to select view and then select some data with additional filtering based on the view.

Answer 1

You can use conditional aggregation:

select count(*), 
       sum(amount) filter (where waga > 5),
       sum(amount) filter (where amount < 5) 
from warehouse 
where createdate = date '2019-01-01'

Answer 2

About the general syntax question you could use WITH clause:

with v as
(
 select id, amount from warehouse where createDate = '2019-01-01'
)
select * from
(
    (select count(*), sum(amount) from v where waga > 5) as count1, 
    (select count(*), sum(amount) from v where amount < 5) as count2
);

(I don't mean it will be faster; it's just a way to use an "inline" view).