Trial Balance SQL Query

select
gb.Period_Name,
cc.concatenated_segments Account_Code,
sum(nvl(gb.period_net_dr_beq,0)-nvl(gb.period_net_cr_beq,0)) PTD_Balance,
sum((gb.begin_balance_dr_beq-gb.begin_balance_cr_beq+gb.period_net_dr_beq-gb.period_net_cr_beq)) YTD_Balance

from
gl_balances gb,
gl_code_combinations_kfv cc

where
cc.code_combination_id=gb.code_combination_id
and actual_flag='A'
and gb.period_name=:P_PERIOD_NAME
and cc.summary_flag='N'
group by
gb.period_name,
cc.concatenated_segments