【问题标题】:Correlated subquery pattern is not supported due to internal error - where not exists correlated subquery由于内部错误,不支持相关子查询模式 - 不存在相关子查询
【发布时间】:2021-02-24 21:04:37
【问题描述】:

我有一个查询给我上面的错误。我的代码如下:

SELECT *,
      dense_rank() OVER (PARTITION BY email
                         ORDER BY priority_score,
                                  comp) AS r
FROM main_query
WHERE NOT EXISTS
   (SELECT name,
           event,
           email,
           report_date
    FROM gm
    WHERE  gm.name= main_query.name
      AND gm.event= main_query.event
      AND gm.email = main_query.email
      AND gm.report_date >= (CURRENT_DATE - 25)::date)
ORDER BY priority_score ASC

我看到克服这些类型错误的一个解决方案是能够在不相关的查询中转换相关的子查询 (sherlock)。因此,我正在寻找使用where not exists 语句但没有相关子查询的其他方法,即在子查询中调用main_query 表((...) from gm left join main_query on(...))。有谁知道这是否可行以及如何做?

任何建议都非常受欢迎,并提前非常感谢!

【问题讨论】:

    标签: sql subquery amazon-redshift correlated-subquery sql-optimization


    【解决方案1】:

    LEFT JOIN 版本有效吗?

    SELECT mq.*,
          dense_rank() OVER (PARTITION BY mq.email
                             ORDER BY mq.priority_score, comp
                            ) AS r
    FROM main_query mq LEFT JOIN
         gm
         ON gm.name = mq.name AND
            gm.event= mq.event AND
            gm.email = mq.email AND
            gm.report_date >= (CURRENT_DATE - 25)::date)
    WHERE gm.name IS NULL  
    ORDER BY priority_score ASC;
    

    如果这不起作用,它应该像这样工作:

    SELECT mq.*,
          dense_rank() OVER (PARTITION BY mq.email
                             ORDER BY mq.priority_score, comp
                            ) AS r
    FROM main_query mq LEFT JOIN
         (SELECT gm.*
          FROM gm
          WHERE gm.report_date >= (CURRENT_DATE - 25)::date)
         ) gm
         ON gm.name = mq.name AND
            gm.event= mq.event AND
            gm.email = mq.email
    WHERE gm.name IS NULL  
    ORDER BY priority_score ASC
    

    【讨论】:

    • 好主意@Gordon Linoff,非常感谢您的帮助,效果很好
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