MySQL查询组由多个条件依赖

Question

我有以下格式的选民数据的MySQL表格（voters）：

id | name | gender | const 

我需要输出以下内容：

const | no. of female voters | no. of male voters | total no. of voters

order by没有。女选民。

我只能提出这个问题：

select const,count(*) from voters where gender='f' group by const order by count(*) desc

我如何得到其他两项罪名？ const表示选区，性别可以是'm'或'f'

Answer 1

在Mysql中你可以这样做

select const,
count(*),
sum(gender='f') female_voters,
sum(gender='m') male_voters
from voters 
group by const 
order by count(*) desc