task: #180

README.md

@@ -79,6 +79,7 @@ Have a good contributing!
     - [2356. Number of Unique Subjects Taught by Each Teacher](./leetcode/easy/2356.%20Number%20of%20Unique%20Subjects%20Taught%20by%20Each%20Teacher.sql)
 2. [Medium](./leetcode/medium/)
     - [176. Second Highest Salary](./leetcode/medium/176.%20Second%20Highest%20Salary.sql)
+    - [180. Consecutive Numbers](./leetcode/medium/180.%20Consecutive%20Numbers.sql)
     - [184. Department Highest Salary](./leetcode/medium/184.%20Department%20Highest%20Salary.sql)
     - [550. Game Play Analysis IV](./leetcode/medium/550.%20Game%20Play%20Analysis%20IV.sql)
     - [570. Managers with at Least 5 Direct Reports](./leetcode/medium/570.%20Managers%20with%20at%20Least%205%20Direct%20Reports.sql)

leetcode/medium/180. Consecutive Numbers.sql

@@ -0,0 +1,35 @@
+/*
+Question 180. Consecutive Numbers
+Link: https://leetcode.com/problems/consecutive-numbers/description/?envType=study-plan-v2&envId=top-sql-50
+
+Table: Logs
+
++-------------+---------+
+| Column Name | Type    |
++-------------+---------+
+| id          | int     |
+| num         | varchar |
++-------------+---------+
+In SQL, id is the primary key for this table.
+id is an autoincrement column starting from 1.
+
+
+Find all numbers that appear at least three times consecutively.
+
+Return the result table in any order.
+*/
+
+WITH prev_next AS (
+    SELECT 
+        id,
+        LAG(num) OVER(ORDER BY id) AS prev_num,
+        LEAD(num) OVER(ORDER BY id) AS next_num
+    FROM Logs
+)
+
+SELECT  DISTINCT l.num AS ConsecutiveNums
+FROM Logs AS l
+LEFT JOIN
+    prev_next AS pn
+    ON l.id = pn.id
+WHERE l.num = pn.prev_num AND pn.prev_num = pn.next_num