清点清楚后如何计算平均值？

Question

我想清点后取平均值。

这是我当前的查询：

SELECT product_id,
         COUNT(DISTINCT shop_id) AS shops,
         year,
         month,
         day
FROM X
GROUP BY  product_id, year, month, day

但是现在，我想取商店的平均值。我尝试过类似的方法，但出现此错误：invalidrequestexception

SELECT product_id,
         AVG(COUNT(DISTINCT shop_id) AS shops) as avg_shops,
         year,
         month,
         day
FROM X
GROUP BY  product_id, year, month, day

Answer 1

试试下面的方法

with cte as
(
SELECT product_id,
         COUNT(DISTINCT shop_id) AS shops,
         year,
         month,
         day
FROM X
GROUP BY  product_id, year, month, day
) select product_id,
         AVG(shops) AS  as avg_shops,
         year,
         month,
         day
FROM cte
GROUP BY  product_id, year, month, day

Answer 2

如果您只想要平均值，请使用子查询：

SELECT AVG(shops)
FROM (SELECT product_id, COUNT(DISTINCT shop_id) AS shops
      FROM X
      GROUP BY product_id, year, month, day
     ) x

清点清楚后如何计算平均值？

How to calculate the average after counting distinctly?

sql

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