SQL架構:

1 Create table If Not Exists Logs (Id int, Num int)
2 Truncate table Logs
3 insert into Logs (Id, Num) values ('1', '1')
4 insert into Logs (Id, Num) values ('2', '1')
5 insert into Logs (Id, Num) values ('3', '1')
6 insert into Logs (Id, Num) values ('4', '2')
7 insert into Logs (Id, Num) values ('
 
5', '1')
8 insert into Logs (Id, Num) values ('6', '2')
9 insert into Logs (Id, Num) values ('7', '2')

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               |
+-----------------+

編寫一個 SQL 查詢，查詢所有至少連續出現三次的數字。

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

例如，給定上面的 Logs 表， 1 是唯一連續出現至少三次的數字。

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

198ms

 1 # Write your MySQL query statement below
 2 
 3 
 4 # SELECT
 5 #     DISTINCT l1.Num ConsecutiveNums
 6 # FROM
 7 #     logs l1,
 8 #     logs l2,
 9 #     logs l3
10 # WHERE
11 #     l1.Id = l2.Id - 1 AND
12 #     l2.Id = l3.Id - 1 AND
13 #     l1.Num = l2.Num AND
14 #     l2.Num = l3.Num
15     
16 select DISTINCT num  AS "ConsecutiveNums" FROM
17 (select num,
18     case 
19         when @record = num then @count:[email protected]+1
20         when @record <> @record:=num then @count:=1 end as n
21     from 
22         Logs ,(select @count:=0,@record:=(SELECT num from Logs limit 0,1)) r
23 ) a
24 where a.n>=3

200ms

 1 # Write your MySQL query statement below
 2 /*
 3 Select DISTINCT l1.Num As ConsecutiveNums from Logs l1, Logs l2, Logs l3 
 4 where l1.Id = l2.Id - 1 and l2.Id = l3.Id - 1 
 5 and l1.Num = l2.Num and l2.Num = l3.Num
 6 */
 7 select distinct(Num) as ConsecutiveNums
 8 from (
 9     select
10     Num,
11     @counter := if(@prev = Num, @counter + 1, 1) as cnt,
12     @prev := Num
13     from Logs y, (select @counter := 1, @prev := NULL) as tmp
14     ) as counts
15 where cnt >= 3;

202ms

 1 # Write your MySQL query statement below
 2 #select Num as ConsecutiveNums from Logs where
 3 
 4 #select Num, count(Id) as counter from Logs group by Num where counter >= 3
 5 
 6 select distinct Num as ConsecutiveNums from
 7     (select 
 8         Num,
 9         @count := if(@prev = (@prev := Num), @count + 1, 1) as counter 
10     from 
11         Logs,
12         (select @prev := -1, @count := 1) as temp
13      ) as result
14 where counter >= 3;

237ms

1 # Write your MySQL query statement below
2 SELECT distinct num as ConsecutiveNums FROM(
3 SELECT id, num, 
4 @pre := @cur,
5 @cur := num,
6 @rep_ct := IF(@pre = @cur, @rep_ct + 1, 1) as rep_ct
7 FROM `Logs` l, (SELECT @pre := null, @cur := 0, @rep_ct := 1) init
8 ) temp WHERE rep_ct >= 3

262ms

 1 # Write your MySQL query statement below
 2 SELECT x.Num as ConsecutiveNums FROM
 3 (SELECT y.Num , SUM(INDEXS) FROM
 4     (SELECT Num,
 5     CASE WHEN @preNum = t.Num then @index else @index := 1
 6     END AS INDEXS,
 7     @index := @index+1,
 8     @preNum := t.Num
 9     FROM Logs t,
10     ([email protected] := null, @index := 1) dse)y
11 WHERE y.INDEXS > 2
12 GROUP BY y.Num)x