Querying the AnalogSummaryHistory view

The AnalogSummaryHistory view is a "wide" view that allows you to return multiple statistics for a single tag within a single query.

The following query returns the minimum, maximum, and average values for the SysTimeSec tag for the last hour.

declare @End datetime

set @End = left(convert(varchar(30),getdate(),120),14)+'00:00'

SELECT Tagname, OPCQuality, Minimum as MIN, Maximum as MAX, Average as AVG

FROM AnalogSummaryHistory

WHERE TagName = 'SysTimeSec'

AND StartDateTime >= dateadd(minute,-60,@End)

AND EndDateTime < @End

AND wwCycleCount = 2

The results are:

Note: When querying the AnalogSummaryHistory view, a data point occuring at the same timestamp as the EndDateTime is not considered part of the query interval. Instead, it is treated as the first data point in the next interval beginning at EndDateTime, and so is not included in the maximum or average value calculations.