select n random rows per specified group

Question

I am struggling to find an optimal solution for the following problem. Suppose I have a table \'Table\' like this:

id    name    report_id
 1    name1    1
          


        

Answer 1

SQLFiddle demo

select ID,NAME,REPORT_ID
from
(
select *, @row:=if(name=@name,@row,0)+1 as rn, @name:=name from 
(select *,RAND() as trand from t) t1,
(select @row:=0,@name:='') tm2 
order by name,trand
) t2
where rn<=10