sql语句需要GROUP BY ，请问应该怎么样添加

需要修改一个sql，写在存储过程中，增加max（c.cust_uuid ） group by c.cust_uuid 的条件 ，不知应怎样修改，请教一下各位

 insert into CUST_CUST_OWNER (OW_UUID,SA_UUID,BR_UUID,OLD_SA_UUID,OLD_BR_UUID,
      REASON,OWNED_DATE,OWNED_TYPE,IS_ACTIVE,CREATED_DATE,UPDATED_DATE,CREATED_BY,UPDATED_BY,
      VERSION,CUST_UUID,OWNED_BY,CUST_NAME,CUST_PHONE,Changed_Type)
      select sys_guid(),C.Sa_Uuid,in$brUuid,d.owed_sa_uuid,d.owed_br_uuid,
      c.reason,sysdate(),'EXCEL','Y',sysdate(),sysdate(),c.created_by,c.updated_by,
      '0',c.cust_uuid,in$userId,c.cust_name,c.cust_phone,'EXCEL'
      from TEMP_CUST_CUST_OWNER c
      left join cust_cust_brsa_owner d on c.cust_uuid = c.cust_uuid and d.br_uuid = c.br_uuid
      where c.import_instance_uuid = in$instanceUuid and c.import_message is null AND C.Cust_Level = 'owner'; 

是不是先吧代码做一个简单的整理，你才好添加进去，不然太乱了

增加max（c.cust_uuid ） group by c.cust_uuid 的条件要做什么？