Help with eloquent

Hello I´m still very new :P

How do I change the next SQL to eloquent?

I have no idea.

select 
case
    WHEN age BETWEEN 15 and 19 THEN '15-19' 
    WHEN age BETWEEN 20 and 24 THEN '20-24'
    WHEN age BETWEEN 25 and 29 THEN '25-29'
    WHEN age BETWEEN 30 and 34 THEN '30-34'
    WHEN age BETWEEN 35 and 39 THEN '35-39'
    WHEN age BETWEEN 40 and 44 THEN '40-44'
    WHEN age BETWEEN 45 and 49 THEN '45-49' 
    WHEN age BETWEEN 50 and 54 THEN '50-54'
    WHEN age > 59 THEN '>59'
    WHEN age is null THEN 'N/A'
end as range,
count(age) as age 
from students where summer_id=1 

GROUP  BY CASE
    WHEN age BETWEEN 15 and 19 THEN '15-19'
    WHEN age BETWEEN 20 and 24 THEN '20-24'
    WHEN age BETWEEN 25 and 29 THEN '25-29'
    WHEN age BETWEEN 30 and 34 THEN '30-34'
    WHEN age BETWEEN 35 and 39 THEN '35-39'
    WHEN age BETWEEN 40 and 44 THEN '40-44'
    WHEN age BETWEEN 45 and 49 THEN '45-49' 
    WHEN age BETWEEN 50 and 54 THEN '50-54'
    WHEN age > 59 THEN '>59'
    WHEN age is null THEN 'N/A'

Thank you