Project Employees I
<p>Table: <code>Project</code></p>

<pre>
+-------------+---------+
| Column Name | Type    |
+-------------+---------+
| project_id  | int     |
| employee_id | int     |
+-------------+---------+
(project_id, employee_id) is the primary key of this table.
employee_id is a foreign key to <code>Employee</code> table.
Each row of this table indicates that the employee with employee_id is working on the project with project_id.
</pre>

<p>&nbsp;</p>

<p>Table: <code>Employee</code></p>

<pre>
+------------------+---------+
| Column Name      | Type    |
+------------------+---------+
| employee_id      | int     |
| name             | varchar |
| experience_years | int     |
+------------------+---------+
employee_id is the primary key of this table. It&#39;s guaranteed that experience_years is not NULL.
Each row of this table contains information about one employee.
</pre>

<p>&nbsp;</p>

<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>

<p>Return the result table in <strong>any order</strong>.</p>

<p>The query result format is in the following example.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> 
Project table:
+-------------+-------------+
| project_id  | employee_id |
+-------------+-------------+
| 1           | 1           |
| 1           | 2           |
| 1           | 3           |
| 2           | 1           |
| 2           | 4           |
+-------------+-------------+
Employee table:
+-------------+--------+------------------+
| employee_id | name   | experience_years |
+-------------+--------+------------------+
| 1           | Khaled | 3                |
| 2           | Ali    | 2                |
| 3           | John   | 1                |
| 4           | Doe    | 2                |
+-------------+--------+------------------+
<strong>Output:</strong> 
+-------------+---------------+
| project_id  | average_years |
+-------------+---------------+
| 1           | 2.00          |
| 2           | 2.50          |
+-------------+---------------+
<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
</pre>

['project-employees-ii']
['Create table If Not Exists Project (project_id int, employee_id int)', 'Create table If Not Exists Employee (employee_id int, name varchar(10), experience_years int)', 'Truncate table Project', "insert into Project (project_id, employee_id) values ('1', '1')", "insert into Project (project_id, employee_id) values ('1', '2')", "insert into Project (project_id, employee_id) values ('1', '3')", "insert into Project (project_id, employee_id) values ('2', '1')", "insert into Project (project_id, employee_id) values ('2', '4')", 'Truncate table Employee', "insert into Employee (employee_id, name, experience_years) values ('1', 'Khaled', '3')", "insert into Employee (employee_id, name, experience_years) values ('2', 'Ali', '2')", "insert into Employee (employee_id, name, experience_years) values ('3', 'John', '1')", "insert into Employee (employee_id, name, experience_years) values ('4', 'Doe', '2')"]
[{"value": "mysql", "text": "MySQL", "defaultCode": "# Write your MySQL query statement below\n"}, {"value": "mssql", "text": "MS SQL Server", "defaultCode": "/* Write your T-SQL query statement below */\n"}, {"value": "oraclesql", "text": "Oracle", "defaultCode": "/* Write your PL/SQL query statement below */\n"}, {"value": "pythondata", "text": "Pandas", "defaultCode": "import pandas as pd\n\ndef project_employees_i(project: pd.DataFrame, employee: pd.DataFrame) -> pd.DataFrame:\n    "}, {"value": "postgresql", "text": "PostgreSQL", "defaultCode": "-- Write your PostgreSQL query statement below\n"}]
{"mysql": ["Create table If Not Exists Project (project_id int, employee_id int)", "Create table If Not Exists Employee (employee_id int, name varchar(10), experience_years int)"], "mssql": ["Create table Project (project_id int, employee_id int)", "Create table Employee (employee_id int, name varchar(10), experience_years int)"], "oraclesql": ["Create table Project (project_id int, employee_id int)", "Create table Employee (employee_id int, name varchar(10), experience_years int)"], "database": true, "name": "project_employees_i", "pythondata": ["Project = pd.DataFrame([], columns=['project_id', 'employee_id']).astype({'project_id':'Int64', 'employee_id':'Int64'})", "Employee = pd.DataFrame([], columns=['employee_id', 'name', 'experience_years']).astype({'employee_id':'Int64', 'name':'object', 'experience_years':'Int64'})"], "postgresql": ["Create table If Not Exists Project (project_id int, employee_id int)", "Create table If Not Exists Employee (employee_id int, name varchar(10), experience_years int)"], "database_schema": {"Project": {"project_id": "INT", "employee_id": "INT"}, "Employee": {"employee_id": "INT", "name": "VARCHAR(10)", "experience_years": "INT"}}}
{"mysql": ["MySQL", "<p><code>MySQL 8.0</code>.</p>"], "mssql": ["MS SQL Server", "<p><code>mssql server 2019</code>.</p>"], "oraclesql": ["Oracle", "<p><code>Oracle Sql 11.2</code>.</p>"], "pythondata": ["Pandas", "<p>Python 3.10 with Pandas 2.2.2 and NumPy 1.26.4</p>"], "postgresql": ["PostgreSQL", "<p>PostgreSQL 16</p>"]}
['Database']