SQL查询SUM和除以不同日期计数

Question

我协助，我正在寻找数据字段的总和，然后想要除以该字段中不同日期的数量。

SUM(CASE WHEN dateResolved IS NOT NULL 
         THEN 1 ELSE 0 
    END) / DISTINCT(dateResolved) AvgPerDay

如果dateResolved中有32个日期，有5个不同的日期，我希望它返回6.4。

Answer 1

默认情况下，它需要整数除法：

SUM(CASE WHEN dateResolved IS NOT NULL 
         THEN 1 ELSE 0 
    END) * 1.0 / COUNT(DISTINCT dateResolved) AvgPerDay

然而，简单count也会起作用：

COUNT(dateResolved) * 1.0 / COUNT(DISTINCT dateResolved) AvgPerDay

COUNT(dateResolved)将忽略null值。

Answer 2

我会这样做：

SUM(CASE WHEN dateResolved IS NOT NULL 
         THEN 1.0 ELSE 0 
    END) / COUNT(DISTINCT dateResolved) as AvgPerDay

但这更简单地表达为：

COUNT(dateResolved) * 1.0 / COUNT(DISTINCT dateResolved) as AvgPerDay