"content":"<p>Table: <code>Project</code></p>\n\n<pre>\n+-------------+---------+\n| Column Name | Type |\n+-------------+---------+\n| project_id | int |\n| employee_id | int |\n+-------------+---------+\n(project_id, employee_id) is the primary key of this table.\nemployee_id is a foreign key to <code>Employee</code> table.\nEach row of this table indicates that the employee with employee_id is working on the project with project_id.\n</pre>\n\n<p> </p>\n\n<p>Table: <code>Employee</code></p>\n\n<pre>\n+------------------+---------+\n| Column Name | Type |\n+------------------+---------+\n| employee_id | int |\n| name | varchar |\n| experience_years | int |\n+------------------+---------+\nemployee_id is the primary key of this table. It's guaranteed that experience_years is not NULL.\nEach row of this table contains information about one employee.\n</pre>\n\n<p> </p>\n\n<p>Write an SQL query that reports the <strong>average</strong> experience years of all the employees for each project, <strong>rounded to 2 digits</strong>.</p>\n\n<p>Return the result table in <strong>any order</strong>.</p>\n\n<p>The query result format is in the following example.</p>\n\n<p> </p>\n<p><strong class=\"example\">Example 1:</strong></p>\n\n<pre>\n<strong>Input:</strong> \nProject table:\n+-------------+-------------+\n| project_id | employee_id |\n+-------------+-------------+\n| 1 | 1 |\n| 1 | 2 |\n| 1 | 3 |\n| 2 | 1 |\n| 2 | 4 |\n+-------------+-------------+\nEmployee table:\n+-------------+--------+------------------+\n| employee_id | name | experience_years |\n+-------------+--------+------------------+\n| 1 | Khaled | 3 |\n| 2 | Ali | 2 |\n| 3 | John | 1 |\n| 4 | Doe | 2 |\n+-------------+--------+------------------+\n<strong>Output:</strong> \n+-------------+---------------+\n| project_id | average_years |\n+-------------+---------------+\n| 1 | 2.00 |\n| 2 | 2.50 |\n+-------------+---------------+\n<strong>Explanation:</strong> The average experience years for the first project is (3 + 2 + 1) / 3 = 2.00 and for the second project is (3 + 2) / 2 = 2.50\n</pre>\n",