SQL 来计算出现次数

Question

我想在我的表中添加 4 个额外的列（右下方 4 个）。

• 统计“设备+日期”的出现次数
• 在与行中的“源”值匹配的分隔列中

这是最后2列的Excel公式，我该如何用SQL编写逻辑？

S1_count_in_the_date:
=COUNTIFS(F:F,F2,A:A,"S1")
--countifs(device+date column, device+date value, source column, "S1")--

S2_count_in_the_date:
=COUNTIFS(F:F,F2,A:A,"S2")
--countifs(device+date column, device+date value, source column, "S2")--

我对 S1_count_in_the_date 的 SQL 尝试：

COUNT(source+device+date) OVER (PARTITION BY device, date)

source	device	date	...	source+device+date	device+date	S1_count_in_the_date	S2_count_in_the_date
S1	A	2021-01-03	…	S1A2021-01-03	A2021-01-03	1	2
S2	A	2021-01-03	…	S2A2021-01-03	A2021-01-03	1	2
S2	A	2021-01-03	…	S2A2021-01-03	A2021-01-03	1	2

提前致谢

Answer 1

最后两列可以是使用group by 单独选择的列。请看下面的 sn-p 看看是否有帮助。

查询：

select 
d.source, d.device, d.date, 
concat(d.source, d.device, cast(d.date as Date)) source_device_date, concat(d.device, cast(d.date as Date)) source_device_date, 
--sdd.sdd_count 
case when sdd.source='S1' then sdd.sdd_count end s1_count, 
case when sdd.source='S2' then sdd.sdd_count end s2_count 
from 
devices d 
join ( 
       select 
            source, device, date, count(*) sdd_count 
       from 
            devices 
       group by source, device, date 
     ) sdd on d.source = sdd.source 
            and d.device=sdd.device 
            and d.date=sdd.date

Fiddle for reference