Select month from a date

Dear All,

im trying to get the date from a date :

in toad it worked but when i use it in the report builder it give an error

the function used was

EXTRACT(MONTH FROM   TO_DATE(ppa.date_earned, 'DD-MON-RR')) < '6'

ppa.date_earned is the field that exist in pay_payroll_actions table

could you please advise how to extract the month & use it in report builder

thanks