Add solution 180 [sql]

Consecutive Numbers

Author: yanglbme

README.md

@@ -89,6 +89,7 @@ Complete [solutions](https://github.com/doocs/leetcode/tree/master/solution) to
 | 153 | [Find Minimum in Rotated Sorted Array](https://github.com/doocs/leetcode/tree/master/solution/153.Find%20Minimum%20in%20Rotated%20Sorted%20Array) | `Array`, `Binary Search` |
 | 177 | [Nth Highest Salary](https://github.com/doocs/leetcode/tree/master/solution/177.Nth%20Highest%20Salary) | `SQL` |
 | 178 | [Rank Scores](https://github.com/doocs/leetcode/tree/master/solution/178.Rank%20Scores) | `SQL` |
+| 180 | [Consecutive Numbers](https://github.com/doocs/leetcode/tree/master/solution/180.Consecutive%20Numbers) | `SQL` |
 | 328 | [Odd Even Linked List](https://github.com/doocs/leetcode/tree/master/solution/328.Odd%20Even%20Linked%20List) | `Linked List` |
 
 

solution/180.Consecutive Numbers/README.md

@@ -0,0 +1,51 @@
+## 连续出现的数字
+### 题目描述
+
+编写一个 SQL 查询，查找所有至少连续出现三次的数字。
+```
++----+-----+
+| Id | Num |
++----+-----+
+| 1  |  1  |
+| 2  |  1  |
+| 3  |  1  |
+| 4  |  2  |
+| 5  |  1  |
+| 6  |  2  |
+| 7  |  2  |
++----+-----+
+```
+
+例如，给定上面的 `Logs` 表， `1` 是唯一连续出现至少三次的数字。
+```
++-----------------+
+| ConsecutiveNums |
++-----------------+
+| 1               |
++-----------------+
+```
+
+### 解法
+联表查询。
+
+```sql
+# Write your MySQL query statement below
+
+select distinct l1.Num ConsecutiveNums 
+from Logs l1
+join Logs l2 on l1.Id = l2.Id - 1
+join Logs l3 on l2.Id = l3.Id - 1
+where l1.Num = l2.Num and l2.Num = l3.Num
+
+
+```
+
+#### Input
+```json
+{"headers": {"Logs": ["Id", "Num"]}, "rows": {"Logs": [[1, 1], [2, 1], [3, 1], [4, 2], [5, 1], [6, 2], [7, 2]]}}
+```
+
+#### Output
+```json
+{"headers":["ConsecutiveNums"],"values":[[1]]}
+```