关联 两个子查询里的表是一样的 关联后查询数据量差异过大

select
a.C_PARTY_ID,b.T_ISSUE_TM
from (
select C_PARTY_ID,C_PLY_TYPE,T_ISSUE_TM
from prd_d_dwd_cust.t_m_bus_report_gp
where C_SRC_ROLE = 'INS_APP' and C_YYTB_FLAG = '0' and C_PLY_TYPE = '0'
and T_LOSE_TM >= '2021-08-09'
and T_ISSUE_TM > '2021-06-09' and T_ISSUE_TM < '2021-08-09'
and C_INSU_OBJ = 'P'
and N_YEARS_TYPE_ynq = '1'
group by C_PARTY_ID,C_PLY_TYPE ,T_ISSUE_TM ) A--4947595
inner join (
select C_PARTY_ID,C_PLY_TYPE,T_ISSUE_TMselect C_PARTY_ID,C_PLY_TYPE,T_ISSUE_TM
from prd_d_dwd_cust.t_m_bus_report_gp
where C_SRC_ROLE = 'INS_APP' and C_YYTB_FLAG = '0' and C_PLY_TYPE = '0'
and T_LOSE_TM >= '2021-08-09'
and T_ISSUE_TM > '2021-06-09' and T_ISSUE_TM < '2021-08-09'
and C_INSU_OBJ = 'P'
and N_YEARS_TYPE_ynq = '1'
group by C_PARTY_ID,C_PLY_TYPE ,T_ISSUE_TM
from prd_d_dwd_cust.t_m_bus_report_gp
where C_SRC_ROLE = 'INS_APP' and C_YYTB_FLAG = '0' and C_PLY_TYPE = '0'
and T_LOSE_TM >= '2021-08-09'
and T_ISSUE_TM > '2021-06-09' and T_ISSUE_TM < '2021-08-09'
and C_INSU_OBJ = 'L'
group by C_PARTY_ID,C_PLY_TYPE ,T_ISSUE_TM
) B on a.C_PARTY_ID = b.C_PARTY_ID --b表4778760
where a.T_ISSUE_TM < b.T_ISSUE_TM ---3114
--上面的sql数据量为3114