Add LATERAL JOIN exercise(s)

[AlisdairO]

[AhmadMuzakkir]

The exercise https://pgexercises.com/questions/joins/tjsub.html can be answered with LATERAL JOIN.

select 
  concat_ws(' ', firstname, surname) as member, 
  name, 
  cost 
from 
  cd.bookings as b 
  inner join cd.members as m using (memid) 
  inner join lateral (
    select 
      facid, 
      name, 
      case when m.memid = 0 then (f.guestcost * b.slots) else (f.membercost * b.slots) end as cost 
    from 
      cd.facilities as f
  ) as f using (facid) 
where 
  cost > 30 
  and starttime >= date '2012-09-14' 
  and starttime < date '2012-09-14' + interval '1 day' 
order by 
  3 desc;

By the way, thank you for the wonderful website.