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

Answer 2

First you need group by to get the calculated columns

 SELECT Customer, COUNT(*) as total_count, SUM(duration) as total_duration
 FROM yourTable
 GROUP BY  Customer

and

 SELECT Customer, Error, COUNT(*) as error_count
 FROM yourTable
 GROUP BY  Customer, Error

Then join back to you table

SELECT t1.Customer, 
       t2.total_count, 
       t1.error, 
       t3.error_count, 
       t2.total_duration
FROM yourTable as t1
JOIN (
     SELECT Customer, COUNT(*) as total_count, SUM(duration) as total_duration
     FROM yourTable
     GROUP BY  Customer
     ) as t2
  ON t1.Customer = t2.Customer
JOIN (
     SELECT Customer, Error, COUNT(*) as error_count
     FROM yourTable
     GROUP BY  Customer, Error
) as t3
 ON t1.Customer = t3.Customer
AND t1.Error = t3.Error
GROUP BY t1.Customer
       , t1.Error