CASE 语句和 GROUP BY 子句中的聚合函数出错

Question

我在更大的查询中使用了以下 CTE，并且根据我的分组方式收到了两条不同的错误消息。

我正在使用 Redash 并使用 Amazon Athena。我可以按 tenant_id 分组，或者我可以按 tenant_id 和名为 "active" 的案例陈述分组。无论哪种方式，我都会收到一个错误。

active_billpay AS
  (SELECT o.tenant_id as tenant_id, CASE WHEN o.created_date >= min(mbpc.created_date) 
     THEN true else false end as active
    FROM reporting.t_order o
    LEFT JOIN reporting.t_me_bill_pay_charge mbpc ON o.tenant_id = mbpc.tenant_id
      WHERE o.retired_date is null
        AND mbpc.retired_date is null
    GROUP by 1),

如果我只按 tenant_id 分组：

Error running query: SYNTAX_ERROR: line 13:32: '(CASE WHEN ("o"."created_date" >= "min"("mbpc"."created_date")) THEN true ELSE false END)' must be an aggregate expression or appear in GROUP BY clause

如果我同时按 tenant_id 和活动进行分组：

Error running query: SYNTAX_ERROR: line 13:32: GROUP BY clause cannot contain aggregations or window functions: ["min"("mbpc"."created_date")]

提前致谢。

Answer 1

我认为您只想按 tenant_id 和 created_date 进行汇总：

 SELECT o.tenant_id as tenant_id,
        (CASE WHEN o.created_date >= MIN(mbpc.created_date) THEN true ELSE false
         END) as active
 FROM reporting.t_order o LEFT JOIN
      reporting.t_me_bill_pay_charge mbpc
      ON o.tenant_id = mbpc.tenant_id
 where o.retired_date is null
 and mbpc.retired_date is null
 group by o.tenant_id, o.created_date

Answer 2

为了应用像 min 这样的聚合函数，SQL 要求您非常具体地说明聚合适用于哪些数据集。即使 SQL 允许您编写的查询，您仍然只会获得每一行的最小值 created_date，而不是每一行 tenant_id.

为了实现我认为您正在尝试做的事情，您应该使用 sub-query 为每个 tenant_id 获取最小值 created_date，然后使用该值告知你的 active 字段。

SELECT o.tenant_id AS tenant_id,
       CASE WHEN o.created_date >= min_created_date THEN TRUE ELSE FALSE END AS active
FROM   reporting.t_order o
       LEFT JOIN
       (SELECT tenant_id, MIN (created_date) AS min_created_date
        FROM   reporting.t_me_bill_pay_charge
        WHERE  retired_date IS NULL) mbpc
           ON o.tenant_id = mbpc.tenant_id
WHERE  o.retired_date IS NULL

一般来说，如果您发现自己试图通过 group by 1 之类的操作来欺骗 SQL 语法要求，则强烈表明您的方法存在缺陷。

CASE 语句和 GROUP BY 子句中的聚合函数出错

Error with aggregate function in a CASE statement and GROUP BY clause

sql

presto

amazon-athena

redash