Select row from a MAX() GROUP BY in SQL Server - sql

Question

I have a table I called Eventos. I have to select the corresponding outTime from the alarm which has the greater inTime.
And I have to do it quickly/optimized. I have about 1 million entries in the table.
This is my code:
SELECT
CadGrupoEventos.Severidade AS Nível,
CadGrupoEquipamentos.Nome AS Grupo,
CadEquipamentos.TAG AS Equipamento,
CadEventos.MensagemPT AS 'Mensagem de alarme',
MAX(Eventos.InTime) AS 'Hora do evento',
Eventos.OutTime AS 'Hora de saída'
FROM
CadGrupoEventos,
CadEquipamentos,
CadEventos,
Eventos,
CadUsuarios,
CadGrupoEquipamentos
WHERE
Eventos.Acked = 0
AND CadGrupoEventos.Codigo = CadEventos.Grupo
AND CadEquipamentos.Codigo = Eventos.TAG
AND CadEventos.Codigo = Eventos.CodMensagem
AND CadGrupoEquipamentos.Codigo = CadEquipamentos.Grupo
GROUP BY
CadGrupoEventos.Severidade,
CadEquipamentos.TAG,
CadEventos.MensagemPT,
CadGrupoEquipamentos.Nome,
Eventos.OutTime
This code, as it is, returns every single entry from the table.
I have to take Eventos.OutTime out of GROUP BY and still get the value of it.

Answer 1

This is just an educated guess based on your description. Notice I used ANSI-92 style joins which are much more explicit. I also used aliases to make this a lot more legible. Your query might look something like this.
select x.Severidade AS Nível,
x.Nome AS Grupo,
x.TAG AS Equipamento,
x.MensagemPT AS [Mensagem de alarme],
x.[Hora do evento],
x.OutTime AS [Hora de saída]
from
(
SELECT cge.Severidade,
cgequip.Nome,
ce.TAG,
cevt.MensagemPT,
MAX(e.InTime) AS [Hora do evento],
e.OutTime
, RowNum = ROW_NUMBER() over(partition by cge.Severidade, ce.TAG, cevt.MensagemPT, cgequip.Nome order by e.OutTime /*maybe desc???*/)
FROM CadGrupoEventos cge
join CadEventos cevt on cge.Codigo = cevt.Grupo
join Eventos e on AND cevt.Codigo = e.CodMensagem
join CadEquipamentos ce on ce.Codigo = e.TAG
join CadGrupoEquipamentos cgequip on cgequip.Codigo = ce.Grupo
cross join CadUsuarios cu --not sure if this is really what you want but your original code did not have any logic for this table
WHERE e.Acked = 0
GROUP BY cge.Severidade,
ce.TAG,
cevt.MensagemPT,
cgequip.Nome,
e.OutTime
) x
where x.RowNum = 1