Suppose we have a table "Person" as below and we need to find out the frequency of each age.

Id LastName FirstName Age City
1 Smith John 33 Newyork
2 Smith Mike 34 Boston
3 Paul Ryan 39 Chicago
4 William Brian 45 Baltimore
5 Rao Sunita 41 Dayton
6 Zing Sue 33 Owings Mills
7 Smith Robert 45 Newyork
8 Paul Zean 33 Chicago
9 Srivastava Hemant 33 Baltimore
10 Rao Venkat 45 Dayton

We could find out the frequency distribution by following the SQL query.

SELECT
    Age,
    COUNT(Age) AS Frequency
FROM
    Persons
GROUP BY
    Age
ORDER BY
    COUNT(Age) DESC