Question

我想要的是每种产品，根据产品的department_id获取该产品的url。递归查询有效，问题所在的行基本上是

select id, title, parent_id from departments where id = prod.department_id

我收到错误ERROR 1054 (42S22): Unknown column 'prod.department_id' in 'where clause'。

如果我用4这样的常量替换这一行中的prod.department_id，那么整个事情就起作用了，只有我为每个产品获得相同的网址。

我无法访问子查询中的每个产品的列，我该怎么做？我在OS X上使用mysql 8.0.12，这是完整的查询：

select id, title, short_description,
(base_price+base_price*tax) as retail_price,

lower(concat('www.someurl.com/',
(with recursive cte (id, title, parent_id) as (
  select id, title, parent_id from departments where id = prod.department_id
  union all (
    select p.id, p.title, p.parent_id
    from departments p inner join cte on cte.parent_id = p.id
  )
) select
GROUP_CONCAT(lower(title) order by id SEPARATOR '/') as path from cte
))) as url

from products prod
inner join featured_products on featured_products.product_id = prod.id;

在内部查询中使用外部查询中的列（相关子查询？）

0 个答案: