Oracle查询在Toad Developer中有效，但在.net应用程序中无效

Question

此查询在Toad开发人员中有效，但在Visual Studio中的.net应用程序中无效（不会返回结果）。任何线索为什么？ 如果省略该行，则查询有效 - 总和（total_cust_cnt）＆gt; = NVL（：customers_out，100）

select   d.region_nbr, pi.city, d.case_id, c.cause_desc cause, sum(total_cust_cnt) customers, d.total_duration_minutes   
from     t_om_cause_of_trouble c, 
         t_om_archive_hist_device d,
         t_om_archive_hist_loc l,
         t_om_pod_info pi
where    c.cause                     = d.cause_of_trouble
and      pi.city                     is not null
and      pi.total_cust_cnt           > 0
and      pi.company                  = l.company
and      pi.distribution_location    = l.distribution_location_nbr
and      l.company                   = d.company
and      l.region_nbr                = d.region_nbr
and      l.outage_system             = d.outage_system
and      l.case_id                   = d.case_id
and      d.first_call_date_time     >= :start_date 
and      d.first_call_date_time     <= :end_date 
and      d.service_request_type      = 'LGTS'
and      d.cause_of_trouble not in
(select distinct cs.cause from t_om_cause_by_summary cs, t_om_cause_of_trouble c
where summary_cause = 'ERROR' and cs.cause = c.cause)
and      d.device_type              <> 'ERR'
and      d.total_duration_minutes   >= 60 * NVL(:hours_out,4)
and      d.total_duration_minutes   > 5
and      d.total_customers_affected >= NVL (:customers_out, 100)
and      to_char(d.region_nbr)      like :region_nbr 
group by d.region_nbr, pi.city, d.case_id, c.cause_desc, d.total_duration_minutes
/* having sum(total_cust_cnt) >= NVL (:customers_out, 100) */

order by d.region_nbr, pi.city, d.case_id
) 
group by region_nbr, city, cause
order by region_nbr, city, cause
) stats
where r.region = stats.region_nbr
)