Calculation of percentage of group count(*)

Question

Select * from Namelist;
Name      Age
Sathish   25
Sathish   65
Sathish   55
Sathish   45
Sathish   35
Jana      55
Jana      25
Jana      10
Bala      55
Bala               


        

Answer 1

This is a slightly sexier version of some of the other answers - note the use of sum(100) to avoid the longer (and more mundane) count(*) * 100 :)

select name, count(*) as count, sum(100) / total as percentage
from namelist
cross join (select count(*) as total from namelist) x
group by 1