Question

我有一个带有数组列的CTE，想通过该ID数组过滤另一列。

with vars as (
  select
    (1, 7, 10000) bubble_ids,
    'Frank' name
)

select * from walruses
inner join tusks on walruses.id = tusks.walrus_id
where (
  name = (select name from vars)
  and tusks.bubble_id IN (select bubble_ids from vars)
);

这将产生以下内容：ERROR: operator does not exist: integer = record

我尝试过取消嵌套-unnest(bubble_ids)-结果是ERROR: record type has not been registered

什么是正确的方法？

Answer 1

(1, 7, 10000)未定义数组。这是一个row constructor，它创建一个匿名记录（具有三个字段）。

array literal用方括号括起来，并且必须以关键字array为前缀，例如array[1, 7, 10000]。另外，您也可以将其写为字符串值：'{1,7,1000}'

当使用CTE作为变量/参数的“容器”时，我通常使用交叉联接使查询可以访问它。打字少

with vars as (
  select
    array[1, 7, 10000] bubble_ids,
    'Frank' as name --<< you need the AS, because name is a keywod
)
select * 
from walruses
  inner join tusks on walruses.id = tusks.walrus_id
  cross join vars v
where name = v.vars
  and tusks.bubble_id = any(v.bubble_ids);

相对于values，我更喜欢select子句来定义常量值。

with vars(bubble_ids, name) as (
  values (array[1, 7, 10000], 'Frank')
)
select * 
from walruses
  inner join tusks on walruses.id = tusks.walrus_id
  cross join vars v
where name = v.vars
  and tusks.bubble_id = any(v.bubble_ids);

通过CTE通过数组列查询

1 个答案: