Report no generate pages when call procedure

Hi,

I created a procedure into mysql, when I try to call the procedure, the result not generate pages, this its the call that I add into Reqport Query:

 call hourly_gas_change($P{DATE}, $P{TANK})   Date its String and Tank its Integer

But if I tried to call the procedure and send directly the data of params, the report show me a correctly result

ex: call hourly_gas_change('2015-10-27', 3)