sql - PostgreSQL 中的递归 CTE 问题

Question

此查询生成从 1 到 4 的数字。

with recursive z(q) as (
  select 1
  union all
  select q + 1 from z where q < 4
  )
select * from z;

但是，如果我修改成这样，

with x as (
  select 1 y
  ),
recursive z(q) as (
  select y from x
  union all
  select q + 1 from z where q < 4
  )
select * from z;

它给了

ERROR: syntax error at or near "z"

我做错了什么？

Answer 1

我认为这是因为RECURSIVE is modifier of WITH statement ，不是公用表表达式 z 的属性，因此您可以像这样使用它:

with recursive
x as (
  select 1 y
),
z(q) as (
  select y from x
  union all
  select q + 1 from z where q < 4
)
select * from z;

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