一、

select
	sum(sex = '1') male, sum(sex = '2')  female 
from
	mchopin

二、

select 
    count(sex='1' or null) male,count(sex='2' or null) female 
from mchopin;

三、

select
	sex, count(distinct(id)) 
from
	mchopin 
group by sex

四、

select
	sum(case sex when '1' then 1 else 0 end)  male,
	sum(case sex when '2' then 1 else 0 end) female 
from
	mchopin

五、

SELECT
	APPLY_ID,
CASE
	WHEN APPLY_ID IN ( 3, 6 ) THEN
	ASTRICT_TIME ELSE NULL 
	END ASTRICT_TIME 
FROM
	mchopin 
WHERE
ASTRICT_TYPE = '2'