是多表连接查询效率高还是多次单表查询效率高啊
天之南极 2013-01-24 11:27:45 SELECT a.*
FROM CBOSS.CALL_BACK_CRM T, cboss.i_user_radius_index_his a
WHERE t.phone_id = a.bill_id
and t.so_nbr = a.so_nbr
and a.act_type = '06'
and t.busi_type = 53
and result_code not in ('0', '00','1-00', '1-0000', '2-00', '2-0000')
and t.create_date >=
to_date('2012-04-15 01:00:00', 'yyyy-mm-dd hh24:mi:ss')
and t.create_date <=
to_date('2012-05-15 01:00:00', 'yyyy-mm-dd hh24:mi:ss')
call_back_CRM 表每天有几千万的数据量,不知道多表连接查询好,还是查询单表后再查询另一个单表效率好,,,
数据库是oralce