Similar question for me. I think I'm close but still not there yet...
I want to know the transactions per minute based on the elapsed time:
```
select
purchases,
Duration*24*60 as minutes,
TxnPerMin
from (
select
event,
count(event) as Purchases,
julianday(max(`datetime`)) - julianday(min(`datetime`)) as duration,
minutes/purchases as TxnPerMin
from table1
where event ='end'
);
```
What kind of subquery do I need for this?