SQL子查询的问题，“错误：无效引用FROM子句项...”

Question

经与SQL（目前使用PostgreSQL）麻烦

我有这个疑问，我需要比较最近项和第二最近的项目：

SELECT p1.*, p2.price_cents FROM "prices" p1 
    INNER JOIN 
    (
     SELECT price_cents, game_id from prices as p WHERE p.game_id = p1.game_id 
     ORDER BY p.created_at DESC LIMIT 1 OFFSET 1 
    ) 
    p2 ON p2.game_id = p1.game_id 

这会产生一些错误：

ERROR: invalid reference to FROM-clause entry for table "p1" 
LINE 1: ...AND p.game_id = p1.game_id... 
         ^
HINT: There is an entry for table "p1", but it cannot be referenced from this part of the query. 

是否有任何理由我不能从子查询访问P1，它是一个存在的问题，如，P1的数据ISN还没有？有没有另一种方法来做到这一点与JOIN？

Answer 1

根据作者的评论

如果需要从最近的第二个条目多列试试这个

SELECT p1.*, (
    SELECT price_cents 
    FROM "prices" p 
    WHERE p1.game_id = p.game_id 
    ORDER BY p.created_at DESC LIMIT 1 OFFSET 1 
) as price_cents 
FROM "prices" p1 

UPDATE，你可以尝试

SELECT * FROM (
    SELECT p.*, (
     SELECT id 
     FROM "prices" 
     WHERE p.game_id = game_id 
     ORDER BY created_at DESC LIMIT 1 OFFSET 1 
    ) AS second_id 
    FROM "prices" p 
) p1 INNER JOIN "prices" p2 ON p1.second_id = p2.id