SQL代码如下

with t1 as(
select b.is_import,b.active_flag,b.last_upd,b.row_id,b.dsig_date,b.vicont_code,b.vendor_id,b.cust_id,b.vcurr_id,b.namt,b.created_by,b.created,b.registdate,b.audit_status,b.prtypedesc 
from UKING_ZHONGFU.BU_INCONT b 
)
select t2.row_id from t1 left join  org_approval_main t2 on t1.row_id=t2.business_id
C#代码如下

                oc.Open();
                //OracleCommand 被标注为已过时
                OracleCommand cmd = oc.CreateCommand();
                cmd.CommandText = @"

with t1 as(
select b.is_import,b.active_flag,b.last_upd,b.row_id,b.dsig_date,b.vicont_code,b.vendor_id,b.cust_id,b.vcurr_id,b.namt,b.created_by,b.created,b.registdate,b.audit_status,b.prtypedesc 
from UKING_ZHONGFU.BU_INCONT b 
)
select t2.row_id from t1 left join org_approval_main t2 on t1.row_id=t2.business_id
";

                OracleDataAdapter da = new OracleDataAdapter(cmd);
                DataSet ds = new DataSet();
                da.Fill(ds,"Table");

在C#中ds得出来是个空的，找了好久不知道是什么原因。请教，谢谢！