Table1 has a "call" column and Table2 has a "pickup" column.
I want to find the call to pickup ratio but can't wrap my head around it.
I am using sqlite. I have tried this
SELECT (SELECT count (call)FROM table1)*100/ (SELECT count (pickup) FROM table2)
but I get a number and not a decimal back
SQLite does integer division. So, 1/2
is 0
rather than 0.5
.
So, the simplest method is to use 100.0
instead of 100
:
SELECT ((SELECT count(call) FROM table1) * 100.0 /
(SELECT count(pickup) FROM table2)
) as call_to_pickup_ratio
This, in turn, runs the ricks of a divide by zero. The solution for that is NULLIF()
:
SELECT ((SELECT count(call) FROM table1) * 100.0 /
(SELECT NULLIF(count(pickup), 0) FROM table2)
Finally, if call
and pickup
are never NULL
, then you can just use COUNT(*)
:
SELECT ((SELECT count(*) FROM table1) * 100.0 /
(SELECT NULLIF(count(*), 0) FROM table2)
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