表“A”有一个条目,但不能从查询的这一部分引用它。

我编写了一个查询,该查询将从名为 allotment :

select a.product_id, 
daterange((lower(a.allotment_period) + concat(n.i - 1, ' days')::interval)::date, 
(upper(a.allotment_period) + concat(n.i, ' days')::interval)::date, '[]') 
from test.allotment as a
cross join(select * from generate_series(1, a.period_length)) as n(i)
where a.id = 2 

我得到这个错误:

ERROR: invalid reference to FROM-clause entry for table "a" LINE 5: cross `join(select * from generate_series(1, a.period_length)... ^ HINT: There is an entry for table "a", but it cannot be referenced from this part of the query. SQL state: 42P01 Character: 250`

我发现了一个类似的问题 SQL joins, “there is an entry for table but it cannot be referenced” 但它不能解决我的问题。有人能解决这个问题吗?