SQL语句求助:同一张表内查询在60秒内重复出现的记录

crane_1981

表T
字段  a,b,c,d 都是字符型  其中c为起始时间,d为结束时间
我的SQL语句如下:
select bb.a,bb.b,
round((to_date(bb.d,'yyyymmdd hh24miss')-to_date(bb.c,'yyyymmdd hh24miss'))*3600*24,0) usage2 from
(select * from T) aa,
(select * from T) bb
where aa.a=bb.a and aa.b=bb.b
and  to_date(aa.c,'yyyymmdd hh24miss')>to_date(bb.c,'yyyymmdd hh24miss')
and (to_date(aa.d,'yyyymmdd hh24miss')-to_date(bb.c,'yyyymmdd hh24miss'))*3600*24<60

但是查出来发现usage2居然有大于60秒的,请帮忙看看

doni

select bb.a,bb.b,
round((to_date(bb.d,'yyyymmdd hh24miss')-to_date(bb.c,'yyyymmdd hh24miss'))*3600*24,0) usage2 from
(select * from T) aa,
(select * from T) bb
where aa.a=bb.a and aa.b=bb.b
and  to_date(aa.c,'yyyymmdd hh24miss')>to_date(bb.c,'yyyymmdd hh24miss')
and (to_date(aa.d,'yyyymmdd hh24miss')-to_date(bb.c,'yyyymmdd hh24miss'))*3600*24<60

看一看两个红色的地方

蓝色蜻蜓

hfgz

select bb.a,bb.b,
round((to_date(bb.d,'yyyymmdd hh24miss')-to_date(bb.c,'yyyymmdd hh24miss'))*3600*24,0) usage2
from T aa,T bb
where aa.a=bb.a and aa.b=bb.b
and  to_date(aa.c,'yyyymmdd hh24miss')>to_date(bb.c,'yyyymmdd hh24miss')
and (to_date(aa.d,'yyyymmdd hh24miss')-to_date(bb.c,'yyyymmdd hh24miss'))*3600*24<60