CTE语法问题

Question

下面的代码有什么问题？

WITH CTE2 AS
(
select 1 as id
union
select 2
),
with CTE3 AS
(
    select * from CTE2
)
select * from CTE3

如果语法错误，则会失败。

Answer 1

代码中不需要额外的WITH。

当使用多个CTE时，您只需用逗号将它们分开，而不需要多个WITH。

WITH CTE2 AS
(
select 1 as id
union
select 2
),
CTE3 AS
(
    select * from CTE2
)

select * from CTE3

Answer 2

不需要第二次WITH

;WITH CTE2 AS
(
  select 1 as id
  union
  select 2
), CTE3 AS
(
   select * from CTE2
)
select * 
from CTE3;