请教SQL问题

以下是我写的SQL语句，速度慢，问题出在下划线这个条件，大家有办法给我解决吗？
select distinct a.str_bill_no, c1.str_staffname as n_dostaff ,
c.str_staffname, d.str_crm_name, e.str_crm_dir, a.n_crm_id,  a.n_sellman_id,
e.str_dir_name, sum(b.d_money * -1)  as totalMoney,
sum((b.d_money * -1) -  b.d_costing_price * (b.n_amount * -1))  as profitMoney,
a.str_operate_code, b.n_account_id, [dbo].[Get_t_mode](a.str_bill_no,a.str_operate_code) as t_mode
from t_mm_Business as a (NoLock)
inner join t_crm_customers as d (NoLock) on d.n_crm_id = a.n_crm_id
inner join t_mm_Business_detail as b (NoLock) on
b.n_stockaccount_id=a.n_stockaccount_id
inner join t_hr_staff as c (NoLock) on c.n_staff_id = a.n_sellman_id
inner join t_hr_staff as c1 (NoLock) on c1.n_staff_id = a.n_dostaff
inner join t_CRM_DIR as e (NoLock) on e.str_crm_dir = d.str_crm_dir
inner join t_crm_customer_types as f (NoLock) on d.e_crm_type = f.e_crm_type
inner join t_account_dir as g(NoLock) on b.n_account_id = g.n_account_id
where (a.dt_chalkup between '2009-8-28 00:00:00:000' and '2009-9-28 23:59:59:000')
and a.n_sellman_id = 1048 and d.str_crm_dir like '0%'
and a.str_operate_code in ('006','106','606')and f.z_crm_type=2
and g.str_depart_coding ='00.01.01' 
and (rtrim(a.str_bill_no)+rtrim(a.str_