按多列请求分组,结果在一行上-Android SQLite
我需要做一些按多列请求分组,结果在一行上-Android SQLite,android,sql,sqlite,Android,Sql,Sqlite,我需要做一些选择计数()分组依据2列(月份和类型)请求。我可以提出以下要求: select Month, Type, Count() from MyTable group by Month, Type 我的问题是,我想使用光标在Android Listview中显示结果: 每月一行 类型的计数(固定数和已知数) 可能是这样的: select Month, Count(Type = A), Count(Type = B), Count(Type = C) from MyTable group
选择<代码>计数()
分组依据
2列(月份和类型)请求。我可以提出以下要求:
select Month, Type, Count()
from MyTable
group by Month, Type
我的问题是,我想使用光标在Android Listview中显示结果:
- 每月一行
- 类型的计数(固定数和已知数)
select Month, Count(Type = A), Count(Type = B), Count(Type = C)
from MyTable
group by Month
数据库
Month | Type
-------- ---------
Feb 15 | A
Feb 15 | B
Dec 15 | A
Dec 15 | A
Dec 15 | B
Dec 15 | C
预期结果
Month | 'COUNT(A)' | 'COUNT(B)' | 'COUNT(C)'
-------- -------------- --------------- -------------
Feb 15 | 1 | 1 | 0
Dec 15 | 2 | 1 | 1
可能吗
select
month,
sum(case when "Type" = 'A' then 1 else 0 end) as "count(a)",
sum(case when "Type" = 'B' then 1 else 0 end) as "count(b)",
sum(case when "Type" = 'C' then 1 else 0 end) as "count(c)"
from
mytable
group by
month