Question

I have the following table:

A  FromA  User
1  NULL   Bob
2  1      Bob
3  1      Chris
4  2      Chris

User is the name of the person who created item A. FromA is the source that the User grabbed it from.

I want to figure out is Chris’ most frequency source.

My query

SELECT count(T1.A GROUP BY T1.User), T1.User
FROM Table T0 
INNER JOIN Table T1 ON T0.FromA=T1.A
WHERE T0.User='Chris'

It should return Bob=2. But it doesn’t seem to work.

Answer 1

Try this:

select t2.user, count(*) Total from t t1
join t t2 on t1.fromA = t2.a
where t1.user = 'Chris'
group by t2.user
order by Total desc
limit 1

The limit 1 will give you just the most frequently used source.

Edit:

inner join will fail to fetch record=>1 | NULL | Bob as ‘fromA’ column has null value. so, switch to left join – Angelin Nadar

Nope. Here is a working example