Use the COUNT() function

The COUNT(*) function works directly in a four-part query, but is not supported inside of the OPENQUERY function.

For example:

SELECT count(*)

FROM History

WHERE TagName = 'SysTimeSec'

AND DateTime >= '2001-12-20 0:00'

AND DateTime <= '2001-12-20 0:05'

AND wwRetrievalMode = 'delta'

AND Value >= 30

The result is:

If you use the OPENQUERY function, you cannot perform arithmetic functions on the COUNT(*) column. However, you can perform the count outside of the OPENQUERY, as follows:

SELECT count(*), count(*)/2 FROM OPENQUERY(INSQL, 'SELECT DateTime, vValue, Quality, QualityDetail

FROM History

WHERE TagName IN ("SysTimeSec")

AND DateTime >= "2002-04-16 03:00:00.000"

AND DateTime <= "2002-04-16 06:00:00.000"

AND wwRetrievalMode = "Delta"

')

The result is: