判断两个时间段是否有重叠

(a,b),(c,d)

判断两段时间是否有重叠 

方法一

select 'yes' from dual where d>a  and c<b;

方法二

select 'yes' from dual where (a, b) overlaps (c,d);

方法三

select 'yes' from dual where a between c and d or d between a and b;