在 BigQuery 中限定分组依据

Question

我已经开始在 BigQuery 中使用 qualify，但 group by 运算符出现问题。

这可以正常工作（尽管我必须输入 where true 这有点奇怪）：

WITH Produce AS (
  SELECT 'Kale' as product, 51 as sales, 'Q1' as quarter UNION ALL
  SELECT 'Kale', 23, 'Q2' UNION ALL
  SELECT 'Kale', 45, 'Q3' UNION ALL
  SELECT 'Kale', 3, 'Q4' UNION ALL
  SELECT 'Apple', 77, 'Q1' UNION ALL
  SELECT 'Apple', 0, 'Q2' UNION ALL
  SELECT 'Apple', 25, 'Q3' UNION ALL
  SELECT 'Apple', 2, 'Q4')
SELECT *
FROM Produce
WHERE true QUALIFY RANK() OVER (PARTITION BY product ORDER BY quarter  DESC) <= 1

但这不起作用：

WITH Produce AS (
  SELECT 'Kale' as product, 51 as sales, 'Q1' as quarter UNION ALL
  SELECT 'Kale', 23, 'Q2' UNION ALL
  SELECT 'Kale', 45, 'Q3' UNION ALL
  SELECT 'Kale', 3, 'Q4' UNION ALL
  SELECT 'Apple', 77, 'Q1' UNION ALL
  SELECT 'Apple', 0, 'Q2' UNION ALL
  SELECT 'Apple', 25, 'Q3' UNION ALL
  SELECT 'Apple', 2, 'Q4')
SELECT product, count(*)
FROM Produce
WHERE true QUALIFY RANK() OVER (PARTITION BY product ORDER BY quarter  DESC) <= 1
group by 1

我是不是做错了什么？抛出的错误是

Syntax error: Expected end of input but got keyword GROUP at [13:1]

Answer 1

您的子句顺序错误。您关心的顺序是：

FROM
WHERE
GROUP BY
HAVING
QUALIFY

所以，试试这个：

SELECT product, count(*)
FROM Produce
WHERE true 
GROUP BY 1
QUALIFY RANK() OVER (PARTITION BY product ORDER BY quarter DESC) <= 1

Answer 2

qualify 预计在 group by:

之后

WITH Produce AS (
  SELECT 'Kale' as product, 51 as sales, 'Q1' as quarter UNION ALL
  SELECT 'Kale', 23, 'Q2' UNION ALL
  SELECT 'Kale', 45, 'Q3' UNION ALL
  SELECT 'Kale', 3, 'Q4' UNION ALL
  SELECT 'Apple', 77, 'Q1' UNION ALL
  SELECT 'Apple', 0, 'Q2' UNION ALL
  SELECT 'Apple', 25, 'Q3' UNION ALL
  SELECT 'Apple', 2, 'Q4')
SELECT product, count(*)
FROM Produce
WHERE true 
group by product, quarter
QUALIFY RANK() OVER (PARTITION BY product ORDER BY quarter  DESC) <= 1

在 BigQuery 中限定分组依据

Qualify group by in BigQuery

sql

teradata

google-bigquery