题目链接：​​点击打开链接​​

题目大意：略。

解题思路：略。

AC 代码

WITH t1 AS(SELECT @num := @num + IF(@pre IS NOT NULL AND log_id - @pre != 1, 1, 0) rw, @pre := log_id cur
FROM Logs, (SELECT @num:=0, @pre:=null) init)

SELECT MIN(cur) start_id, MAX(cur) end_id
FROM t1
GROUP BY rw