Use columns of a variant type with functions

If you use a column of a variant type as the parameter for some functions, SQL Server returns a syntax error. However, the error is not passed to the Historian OLE DB provider to return to clients.

For example, in the following query, the rounding is specified for the vValue column, which is of type variant. The query does not work, but no error is returned by the Historian OLE DB provider.

SELECT DateTime, round(vValue, 2)

FROM History

WHERE TagName IN ('SysTimeSec')

AND DateTime = getdate()

AND wwRetrievalMode = 'Cyclic'