select sum( case when sex = '男' then 1 else 0 end) 男生, sum( case when sex = '女' then 1 else 0 end) 女生 from customer
select sum(case when sex='男' then 1 else 0 end) as 男生, sum(case when sex='女' then 1 else 0 end) as 女生, sum(case when sex not in ('男','女') then 1 else 0 end) as 未知 from customer
sum( case when sex = '女' then 1 else 0 end) 女生
from customer
sum(case when sex='女' then 1 else 0 end) as 女生,
sum(case when sex not in ('男','女') then 1 else 0 end) as 未知
from customer