MySQL判断时间段是否重合的两种方法

-- 时间段 a,b  
SELECT * FROM table WHERE
       (start_time >= a and end_time <= b) -- 被包含了
    or (end_time >= a and end_time <=b)
    or (start_time >= a and start_time <=b)
    or (start_time <= a and end_time >=b)

SELECT * FROM table WHERE
    (end_time >= a and end_time <=b)
    or (start_time >= a and start_time <=b)
    or (start_time <= a and end_time >=b);

SELECT * FROM table WHERE not (start_time > b or end_time < a);