Crystal Reports Substr in Crystal reports

Message

     Hi All,

I am very new to crystal reports, I am trying to create a report on this query.

"select substr(employee_id,1,5), col2,col3,col4 from employee "

But whatever I do its done only at report level (tried with left function). The query that is sent to oracle database is like this

"select employee_id,col2,col3,col4 from employee" 
and the filter is applied on the resultset fetched

how do i achieve substr in my query through crystal reports

Thanks much in advance
Sebin