I got the zeroes when trying your query in SQLite3 when I declared the Salary as INTEGER . You haven't shown the declaration of the table, though, so it's just a guess.

What helped was to cast the divisor as real:

SELECT empid, MAX(Salary), MIN(Salary),
       ((MAX(Salary) - MIN(Salary)) / CAST(MIN(Salary) AS REAL))
FROM Salary
GROUP BY empid;

But if you need to result multiplied by 100, you can just multiply the subtraction before doing the division:

SELECT empid, MAX(Salary), MIN(Salary),
       100 * (MAX(Salary) - MIN(Salary)) / MIN(Salary)
FROM Salary
GROUP BY empid;