query is cancelled

I am trying to run an SQL statement that would sum 25 columns of a certain table with a large number of records.
Using the same select statement with a condition that will yield to a few query result, the select statement generates the expected output. I would like to know what might be the cause of cancellation of the execution of the said SQL which I encounter whenever I use condition that would generate a large query result? Is there a maximum number for records returned?

Your wait time may be expiring with the large return set you might want to increase the time you can wait. You would change that on your connection object.

con1.CommandTimeout = 1000

I think

Phil