Counting total rows and grouping by a column in mysql

Question

So i\'ve been looking at this one for a while and I can\'t seem to figure it out.

I have a mysql table with the following format and sample data:

ID, Cus         


        

Answer 1

You could use a join on a subselect with the sum for customer You could use a join on a subselect with the sum for customer

select a.customer, a.error, t.num_row, t.duration 
from my_table   a
inner join ( 
    select  customer, count(*) as num_row, sum(duration) duration 
    from my_table 
    group by customer 
  ) t on t.customer  = a.customer