176. Second Highest Salary

Medium (Trung bình) SQL 🔗 Xem trên LeetCode

📋 Đề Bài

Table: Employee

+-------------+------+
| Column Name | Type |
+-------------+------+
| id          | int  |
| salary      | int  |
+-------------+------+
id is the primary key column for this table.
Each row of this table contains information about the salary of an employee.

Write an SQL query to report the second highest salary from the Employee table. If there is no second highest salary, the query should report null.

The query result format is in the following example.

Example 1:

Input: 
Employee table:
+----+--------+
| id | salary |
+----+--------+
| 1  | 100    |
| 2  | 200    |
| 3  | 300    |
+----+--------+
Output: 
+---------------------+
| SecondHighestSalary |
+---------------------+
| 200                 |
+---------------------+

Example 2:

Input: 
Employee table:
+----+--------+
| id | salary |
+----+--------+
| 1  | 100    |
+----+--------+
Output: 
+---------------------+
| SecondHighestSalary |
+---------------------+
| null                |
+---------------------+

💻 Lời Giải

SQL 0176-second-highest-salary.sql

# Write your MySQL query statement below

SELECT (
    SELECT DISTINCT salary
    FROM Employee
    ORDER BY salary DESC
    LIMIT 1 OFFSET 1
) AS SecondHighestSalary;