是的,select中的sub select只需要返回一行,您的CTE中有许多行.
如果你做了这样的事,你的质疑对我来说更有意义:
With some_table as (
SELECT * FROM VALUES
(1, 'new york', 10, '2020-01-01'::date),
(1, 'new york', 10, '2020-02-01'::date),
(2, 'christchurch', 20, '2021-01-01'::date)
v(id, city, time_id, date1)
), cte as (
Select
min(date1) as min_date,
max(date1) as max_date,
id,
city,
time_id
FROM some_table
GROUP BY 3,4,5
), range as (
SELECT
id, city, time_id,
dateadd('month', row_number()over(partition by id, city, time_id ORDER BY null), min_date) as date_expand
FROM table(generator(rowcount =>12*36))
CROSS JOIN cte
)
Select * from range;
但如果你的CTE变成这样:
With cte as (
Select
min(date1) as min_date,
max(date1) as max_date
FROM some_table
), range as (
SELECT
dateadd('month', row_number()over(ORDER BY null), (select min_date from cte)) as date_expand
FROM table(generator(rowcount =>2*4))
)
Select * from range;
这是可行的,因为只返回一个min_date值.
或者你可以找到最小的min_日期,比如:
WITH cte as (
Select
min(date1) as min_date,
max(date1) as max_date,
id,
city,
time_id
FROM some_table
GROUP BY 3,4,5
), range as (
SELECT
dateadd('month', row_number()over(ORDER BY null), (select min(min_date) from cte)) as date_expand
FROM table(generator(rowcount =>2*3))
)
Select * from range;