Per prima cosa devi raggruppare per per ottenere le colonne calcolate
SELECT Customer, COUNT(*) as total_count, SUM(duration) as total_duration
FROM yourTable
GROUP BY Customer
e
SELECT Customer, Error, COUNT(*) as error_count
FROM yourTable
GROUP BY Customer, Error
Quindi unisciti di nuovo al tuo tavolo
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