text: --1285. Find the Start and End Number of Continuous Ranges
  --
  --Table: Logs
  --
  --+---------------+---------+
  --| Column Name   | Type    |
  --+---------------+---------+
  --| log_id        | int     |
  --+---------------+---------+
  --id is the primary key for this table.
  --Each row of this table contains the ID in a log Table.
  --
  --Since some IDs have been removed from Logs. Write an SQL query to find the start and end number of continuous ranges in table Logs.
  --
  --Order the result table by start_id.
  --
  --The query result format is in the following example:
  --
  --Logs table:
  --+------------+
  --| log_id     |
  --+------------+
  --| 1          |
  --| 2          |
  --| 3          |
  --| 7          |
  --| 8          |
  --| 10         |
  --+------------+
  --
  --Result table:
  --+------------+--------------+
  --| start_id   | end_id       |
  --+------------+--------------+
  --| 1          | 3            |
  --| 7          | 8            |
  --| 10         | 10           |
  --+------------+--------------+
  --The result table should contain all ranges in table Logs.
  --From 1 to 3 is contained in the table.
  --From 4 to 6 is missing in the table
  --From 7 to 8 is contained in the table.
  --Number 9 is missing in the table.
  --Number 10 is contained in the table.
  --
  --# Write your MySQL query statement below
  select l1.log_id as start_id, min(l2.log_id) as end_id
  from
  (
  select log_id from Logs where log_id - 1 not in (select log_id from Logs)
  ) l1,
  (
  select log_id from Logs where log_id + 1 not in (select log_id from Logs)
  ) l2
  where l1.log_id <= l2.log_id
  group by l1.log_id;
  