Filter 1 columns data into 3 columns
Just use SUM() and a CASE statement: 

SELECT sum(case when zcsms_studentgender=11 then 1 else 0 end) as malestudents,
       sum(case when zcsms_studentgender=12 then 1 else 0 end) as femalestudents,
       sum(case when zcsms_studentgender in (11,12) then 1 else 0 end) as totalstudents
FROM zcsms_studentdefinition
WHERE zcsms_studentactive = 'Y';