case when in a projection definition

projection.php

<?php
// …
    public function createProjection()
    {
        $age = <<<FIELD
case
  when age(%published_at) > '1 year 1 day'::interval then date_trunc('year', age(%published_at))
  when age(%published_at) > '1 month 1 day'::interval then date_trunc('month', age(%published_at))
  when age(%published_at) > '1 day'::interval then date_trunc('day', age(%published_at))
  when age(%published_at) > '1 hour'::interval then date_trunc('hour', age(%published_at))
  else date_trunc('minutes', age(%published_at))
end
FIELD;
        return parent::createProjection()
            ->setField('age', $age, 'interval')
            ;
    }