Codecademy SQL SpeedySpoon Exercise 9

select *,
  case name
    when 'kale-smoothie'    then 'smoothie'
    when 'banana-smoothie'  then 'smoothie'
    when 'orange-juice'     then 'drink'
    when 'soda'             then 'drink'
    when 'blt'              then 'sandwich'
    when 'grilled-cheese'   then 'sandwich'
    when 'tikka-masala'     then 'dinner'
    when 'chicken-parm'     then 'dinner'
    else 'other'
  end as category
from order_items
order by id
limit 100;

-- percentages

select
  case name
    when 'kale-smoothie'    then 'smoothie'
    when 'banana-smoothie'  then 'smoothie'
    when 'orange-juice'     then 'drink'
    when 'soda'             then 'drink'
    when 'blt'              then 'sandwich'
    when 'grilled-cheese'   then 'sandwich'
    when 'tikka-masala'     then 'dinner'
    when 'chicken-parm'     then 'dinner'
    else 'other'
  end as category, round(1.0 * sum(amount_paid) /
    (select sum(amount_paid) from order_items) * 100, 2) as pct
from order_items
group by 1
order by 2 desc;