замените имя столбца и попробуйте это:
SELECT iName,
COUNT(iName) AS `Count`,
concat(FORMAT(((COUNT(iName) * 100) / NewPeople.iCount),2),'%') AS `Percentage`
FROM people, (SELECT COUNT(iName) AS iCount FROM people) NewPeople
GROUP BY iName;
Вывод:
Name Count Percentage
Sathish 5 50.00%
Jana 3 30.00%
Bala 2 20.00%