create table test_aa (c1 date);
insert into test_aa values (to_date('2018-06-05 19:55:44','yyyy-mm-dd hh24:mi:ss'));
insert into test_aa values (to_date('2018-06-05 03:55:44','yyyy-mm-dd hh24:mi:ss'));
insert into test_aa values (to_date('2018-06-06 13:55:44','yyyy-mm-dd hh24:mi:ss'));
commit;

select *
  from test_aa
 where (c1 >= trunc(sysdate - 1) + 18 / 24 and c1 < trunc(sysdate))
    or (c1 >= trunc(sysdate - 1) and c1 < trunc(sysdate - 1) + 6 / 24);

这是查看昨天18点到24点之间和昨天凌晨零点到早晨6点之间记录的sql语法。