基於左側字符計數？

Question

我有一個表，看起來像這樣：

ID  Location 
1  AAA123 
1  AAA133 
1  AAA832 
1  BBB929 
1  BBB420 

我怎麼能算和組由前3個字符，這樣的結果是這樣的：

ID  AAA_Count  BBB_count 
1  3    2 

我想是這樣的：

select [ID], Location, 
case when left(location, 3) = 'AAA' then count(location) end as 'AAA', 
case when left(location, 3) = 'BBB' then count(location) end as 'BBB', 
from Table 
group by [ID], left(location, 3) 

任何幫助表示讚賞。

謝謝。

Answer 1

你需要

select [ID], 
count(case when left(location, 3) = 'AAA' then 1 end) as [AAA], 
count(case when left(location, 3) = 'BBB' then 1 end) as [BBB] 
from Table 
group by [ID] 

Answer 2

如果你想要一個基於行的解決方案，而不是基於列的解決方案，你可以使用：

Select ID, left(location, 3) as Chars, count(1) as Counts 
from Table group by ID, left(location, 3);