Question

The title explains my whole question. Here’s the query:

select
date_format(now(), '%Y') - date_format(date_of_birth, '%Y') age,
IF(date_format(now(), '%Y') - date_format(date_of_birth, '%Y') < 18,
  'Under 18',
  IF(date_format(now(), '%Y') - date_format(date_of_birth, '%Y') <= 24,
    '19 to 24',
    IF(date_format(now(), '%Y') - date_format(date_of_birth, '%Y') <= 34,
      '25 to 34',
      'Over 34'))) age_range
from customer

Answer 1

I suggest a combination of case and a nested query – something like:

select s.age,
       case when s.age < 18 then 'Under 18'
            when s.age <= 24 then '19 to 24'
            when s.age <= 34 then '25 to 34'
            else 'Over 34'
       end case as age_range
from (select date_format(now(), '%Y') - date_format(date_of_birth, '%Y') as age
      from customer) s