Server Administration Guide - Access the Values for a Historic View (SQL Query Configuration Settings)

Access the Values for a Historic View

You can access the values that are produced by a Historic View’s algorithms by querying the table for the Historic View. To do this, you can use an SQL Query or a query from another application such as Crystal Reports. In your SQL Query, you will need to use the Summary field to define the result columns that you want to query. For example, if you wanted to query the top 10 results in the Average and Sum result columns of a Historic View for a point with the ID of 23338, you would define the SQL Query as:

SELECT TOP(10) * FROM HistoricView1 WHERE Summary='AVERAGE' OR Summary='Sum' AND ID=23338.

Where HistoricView1 is the name of the Historic View you want to query (as defined when the Historic View was configured, see Create a Historic View).

Take care with End and End Last Historic Algorithms used on clients, or with Geo SCADA Expert features, that run in Local Time with Daylight Saving Time. Ensure that the start and end times specified for the sample interval do not coincide exactly with the time at which the clock jumps backward. Include a small offset in the sample time, to offset the calculation to avoid the sample end or start time exactly matching the time that the clock jumps backward at the transition from Daylight Saving Time to Standard Time. A small offset of 1s or even 1ms should suffice. For more information about Daylight Saving Time, see The Effects of Daylight Saving Time Adjustments.