求教 oracle查询中
wlyve 2013-08-29 09:53:32 where a.vip_no(+) = b.vip_no
and b.vip_no = c.vip_no
and a.cons_time(+) between '20130101000000' and '20130822235959' --
and b.issu_time < '20130228000000'
and b.curr_valid_date>= '20130823'
and a.cancel_flag(+) ='0'
(+)表示什么意思 看不懂啊。。