"content":"<p>Table: <code>Employee</code></p>\n\n<pre>\n+-------------+------+\n| Column Name | Type |\n+-------------+------+\n| id | int |\n| salary | int |\n+-------------+------+\nid is the primary key column for this table.\nEach row of this table contains information about the salary of an employee.\n</pre>\n\n<p> </p>\n\n<p>Write an SQL query to report the second highest salary from the <code>Employee</code> table. If there is no second highest salary, the query should report <code>null</code>.</p>\n\n<p>The query result format is in the following example.</p>\n\n<p> </p>\n<p><strong>Example 1:</strong></p>\n\n<pre>\n<strong>Input:</strong> \nEmployee table:\n+----+--------+\n| id | salary |\n+----+--------+\n| 1 | 100 |\n| 2 | 200 |\n| 3 | 300 |\n+----+--------+\n<strong>Output:</strong> \n+---------------------+\n| SecondHighestSalary |\n+---------------------+\n| 200 |\n+---------------------+\n</pre>\n\n<p><strong>Example 2:</strong></p>\n\n<pre>\n<strong>Input:</strong> \nEmployee table:\n+----+--------+\n| id | salary |\n+----+--------+\n| 1 | 100 |\n+----+--------+\n<strong>Output:</strong> \n+---------------------+\n| SecondHighestSalary |\n+---------------------+\n| null |\n+---------------------+\n</pre>\n",