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What you are looking for is a subselect, which works in Oracle and (I think) in MySQL 4.x, but not in older version of MySQL. For this reason, I do not recommend trying to do it that way.
Instead, you should first make the count query and store the count in a PHP variable, then use that var in your query against the events table. This has the nice side effect of dealing with the case where there are no records by returning 0.
This is far less complicated that the subselect and works everywhere.
Dennis