Postgresql

Question

我有疑问。

https://dbfiddle.uk/?rdbms=postgres_12&fiddle=1b3a39357a5fe028f57b9ac26d147a1d

SELECT users.id as user_ids,
       (SELECT
           ARRAY_AGG(DISTINCT CONCAT(user_has_bonuses.bonus_id)) as bonus_ids
        FROM user_has_bonuses
            WHERE user_has_bonuses.user_id = users.id) as BONUS_IDS,
       (SELECT
           ARRAY_AGG(DISTINCT CONCAT(bonuses.bonus_id))
        FROM bonuses
            WHERE bonuses.bonus_id IN (BONUS_IDS)
            ) AS bonusIds
FROM users;

我遇到以下错误：

[42703] ERROR: column "bonus_ids" does not exist Hint: Perhaps you meant to reference the column "bonuses.bonus_id".

如何正确使用这个查询？

Answer 1

我认为您正在寻找横向连接。你的例子太做作了，没有实际意义，但逻辑是：

select u.id, ub.*, b.*
from users u
cross join lateral (
    select array_agg(distinct ub.bonus_id) bonus_id
    from user_has_bonus ub
    where ub.user_id = u.id
) ub
cross join lateral (
    select ...
    from bonuses b
    where b.bonus_id = any(ub.bonus_id)
) b

与使用内联子查询相反，您可以在下一个子查询中引用一个子查询中的列 - 如第二个子查询的 where 子句所示。

请注意，您要使用 any() 而不是 in 来检查值是否属于数组。

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postgresql-12