select c.nombre as Comercializadora,
m.idTarifa as id_tarifa, m.fecha as fecha,
m.hora as hora,ROUND(sum(m.medida),3) as medida

from MedidasHorarias m
LEFT JOIN Clientes c on c.id = m.idComercializadora

where m.idComercializadora = 8

group by m.idTarifa, m.fecha, m.hora
having year(m.fecha) = "2016"
and month(m.fecha) = "01"
and m.idTarifa = 1

order by m.fecha,m.hora asc;