List facilities with more than 1000 slots booked
Question
Produce a list of facilities with more than 1000 slots booked. Produce an output table consisting of facility id and slots, sorted by facility id.Schema reminder ▼
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Answers and Discussion Show
select facid, sum(slots) as "Total Slots"
from cd.bookings
group by facid
having sum(slots) > 1000
order by facid
It turns out that there's actually an SQL keyword designed to help with the filtering of output from aggregate functions. This keyword is HAVING.
The behaviour of HAVING is easily confused with that of WHERE. The best way to think about it is that in the context of a query with an aggregate function, WHERE is used to filter what data gets input into the aggregate function, while HAVING is used to filter the data once it is output from the function. Try experimenting to explore this difference!