Group by week:

select COUNT(id) as total_count, WEEKOFYEAR(created_at) AS yr_week from analytics where is_redeemed = 1 and created_at >= NOW() - INTERVAL 7 WEEK group by yr_week

Group by month:

select COUNT(id) as total_count, MONTH(created_at) AS yr_week from analytics where is_redeemed = 1 and created_at >= NOW() - INTERVAL 3 MONTH group by yr_week