GROUP BY

The Historian OLE DB Provider supports the use of GROUP BY in a SELECT statement. GROUP BY combines records with identical values in the specified field list into a single record. Then, you can compute an aggregate value for the grouped records. The aggregate column does not exist in the actual table. Another calculated column is created with the results.

Example: Group Messages by User Name and Topic

SELECT username, topic, COUNT(*) FROM ihmessages
WHERE timestamp >= '1-dec-2001 00:00:00'
AND timestamp <= '7-dec-2001 00:00:00'
GROUP BY username, topic ORDER BY username, topic