Source:

Description:

Write a SQL query to find all numbers that appear at least three times consecutively.

+----+-----+| Id | Num |+----+-----+| 1 | 1 || 2 | 1 || 3 | 1 || 4 | 2 || 5 | 1 || 6 | 2 || 7 | 2 |+----+-----+

For example, given the above Logs table, 1 is the only number that appears consecutively for at least three times.

+-----------------+| ConsecutiveNums |+-----------------+| 1               |+-----------------+

 

Solution:

select distinct l1.numfrom Logs l1     join Logs l2 on l1.id=l2.id-1     join Logs l3 on l1.id=l3.id-2where l1.num=l2.num and l2.num=l3.num