Question

我陷入了条件雪花选择sql。当它们具有相应的分类值时，我正在尝试计算ID。我将不胜感激。

谢谢

SELECT 
YEAR(DATETIME) AS YEAR, 
WEEKOVERYEAR(DATETIME) AS WEEK,
COUNT(CASE WHEN ID THEN CATEGORY = 'A')
from table 
group by week, year;

Answer 1

这是一种方法：

SELECT YEAR(DATETIME) AS YEAR, 
       WEEKOVERYEAR(DATETIME) AS WEEK,
       SUM(CASE WHEN CATEGORY = 'A' THEN 1 ELSE 0 END) as num_a
FROM table 
GROUP BY week, year;

Answer 2

雪花支持COUNT_IF：

返回满足条件的记录数。

汇总功能
COUNT_IF( <condition> )

SELECT YEAR(DATETIME) AS YEAR, 
       WEEKOVERYEAR(DATETIME) AS WEEK,
       COUNT_IF(CATEGORY = 'A') AS num_a
FROM tab
GROUP BY week, year;

Answer 3

COUNT（）计算不为空的行数。如果要在ID不为空且CATEGORY ='A'时使用

COUNT(CASE WHEN ID IS NOT NULL AND CATEGORY = 'A' THEN TRUE ELSE NULL END)

将为您提供，或者您可以使用戈登答案中的SUM

SUM(CASE WHEN ID IS NOT NULL AND CATEGORY = 'A' THEN 1 ELSE 0 END)

或者您可以将雪花IFF用作同一件事的缩写，这就是我的做法

SUM( IFF( ID IS NOT NULL AND CATEGORY = 'A', 1, 0))

Answer 4

你应该/可以使用 IFF() 因为 case when 在有多个条件时更合适。

SELECT 
    YEAR(DATETIME) AS YEAR, 
    WEEKOVERYEAR(DATETIME) AS WEEK,
    COUNT(IFF(CATEGORY = 'A',ID,NULL)) as count
    from table 
    group by week, year;

选择雪花SQL时的条件情况

4 个答案: