mirror of
https://gitee.com/coder-xiaomo/leetcode-problemset
synced 2025-01-10 18:48:13 +08:00
72 lines
2.3 KiB
HTML
72 lines
2.3 KiB
HTML
<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> </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's guaranteed that experience_years is not NULL.
|
|
Each row of this table contains information about one employee.
|
|
</pre>
|
|
|
|
<p> </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> </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>
|