Question

Could you please help me with the unknownComputation in the SQLite statement below?

select t1.attr, unknownComputation as ratio
from t1
group by t1.attr
order by ratio

unknownComputation should be (count(t1.attr) for which there exists t2.url = t1.link) / count(t1.attr)

Not all URLs from t1 are in t2 and I’d like to find these ratios and group them by t1.attr

Answer 1

With the information you provided, perhaps this should do:

select t1.attr, count(t2.url) / count(t1.attr) as ratio
from t1
left join t2 on t2.url = t1.link
group by t1.attr
order by ratio

However, this considers that one t1 can have 0 or many t2