在MySQL中查找可用的时间范围

Question

I am trying to find if a time frame is availability from UNIX start to UNIX end. I have data like:

id start      end
1  1309383000 1309390200
2  1305115200 1305129600
3  1305374400 1305403200

I am trying to run a query where I have a given start and end, and checking to see if this slow is taken. However, a start can start when another entry ends. I have tried a lot of different ways, cannot get it to work right. Any help is appreciated.

I am using PHP to call the query. However, I would like to do it in pure MySQL if possible.

Answer 1

select  if(max(end) >= $end, max(end), $end) - 
        if(min(start) <= $start, min(start), $start) - 
        if(sum(end - start) is null, 0, sum(end - start))  as FreeTime
where end > $start and start < $end