MSSQL MAX returns all results? - sql

Question

I have tried the following query to return the highest P.Maxvalue for each ME.Name from the last day between 06:00 and 18:00:
SELECT MAX(P.MaxValue) AS Value,P.DateTime,ME.Name AS ID
FROM vManagedEntity AS ME INNER JOIN
Perf.vPerfHourly AS P ON ME.ManagedEntityRowId = P.ManagedEntityRowId INNER JOIN
vPerformanceRuleInstance AS PRI ON P.PerformanceRuleInstanceRowId = PRI.PerformanceRuleInstanceRowId INNER JOIN
vPerformanceRule AS PR ON PRI.RuleRowId = PR.RuleRowId
WHERE (ME.ManagedEntityTypeRowId = 2546) AND (pr.ObjectName = 'VMGuest-cpu') AND (pr.CounterName LIKE 'cpuUsageMHz') AND (CAST(p.DateTime as time) >= '06:00:00' AND CAST(p.DateTime as time) <='18:00:00') AND (p.DateTime > DATEADD(day, - 1, getutcdate()))
group by ME.Name,P.DateTime
ORDER by id
but it seems to return each MaxValue for each ID instead of the highest?
like:
Value DateTime ID
55 2018-02-19 12:00:00.000 bob:vm-100736
51 2018-02-19 13:00:00.000 bob:vm-100736
53 2018-02-19 14:00:00.000 bob:vm-100736
52 2018-02-19 15:00:00.000 bob:vm-100736
52 2018-02-19 16:00:00.000 bob:vm-100736
51 2018-02-19 17:00:00.000 bob:vm-100736
54 2018-02-19 18:00:00.000 bob:vm-100736
51 2018-02-20 06:00:00.000 bob:vm-100736
51 2018-02-20 07:00:00.000 bob:vm-100736
53 2018-02-20 08:00:00.000 bob:vm-100736
52 2018-02-20 09:00:00.000 bob:vm-100736
78 2018-02-19 12:00:00.000 bob:vm-101
82 2018-02-19 13:00:00.000 bob:vm-101
79 2018-02-19 14:00:00.000 bob:vm-101
78 2018-02-19 15:00:00.000 bob:vm-101
79 2018-02-19 16:00:00.000 bob:vm-101
77 2018-02-19 17:00:00.000 bob:vm-101
82 2018-02-19 18:00:00.000 bob:vm-101
82 2018-02-20 06:00:00.000 bob:vm-101
79 2018-02-20 07:00:00.000 bob:vm-101
81 2018-02-20 08:00:00.000 bob:vm-101
82 2018-02-20 09:00:00.000 bob:vm-101
155 2018-02-19 12:00:00.000 bob:vm-104432
there is one value per hour for each id hence twelve results for each id
does MAX not work in this way i want ?
Thanks
expected view like this :
Value DateTime ID
55 2018-02-19 12:00:00.000 bob:vm-100736
82 2018-02-19 13:00:00.000 bob:vm-101
etc

Answer 1

If you're using group by on datetime and id, you'll get all datetimes and all ids, it's that simple.
If you don't need exact time, you can group by date only:
SELECT MAX(P.MaxValue) AS Value, cast(P.DateTime as date) as dat, ME.Name AS ID
...
group by ME.Name, cast(P.DateTime as date)
Or if you do, you may use not exists clause instead of group by.