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+<h2><a href="https://leetcode.com/problems/students-and-examinations/">1280. Students and Examinations</a></h2><h3>Easy</h3><hr><div class="sql-schema-wrapper__3VBi"><a class="sql-schema-link__3cEg">SQL Schema<svg viewBox="0 0 24 24" width="1em" height="1em" class="icon__1Md2"><path fill-rule="evenodd" d="M10 6L8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"></path></svg></a></div><div><p>Table: <code>Students</code></p>
+
+<pre>+---------------+---------+
+| Column Name   | Type    |
++---------------+---------+
+| student_id    | int     |
+| student_name  | varchar |
++---------------+---------+
+student_id is the primary key (column with unique values) for this table.
+Each row of this table contains the ID and the name of one student in the school.
+</pre>
+
+<p>&nbsp;</p>
+
+<p>Table: <code>Subjects</code></p>
+
+<pre>+--------------+---------+
+| Column Name  | Type    |
++--------------+---------+
+| subject_name | varchar |
++--------------+---------+
+subject_name is the primary key (column with unique values) for this table.
+Each row of this table contains the name of one subject in the school.
+</pre>
+
+<p>&nbsp;</p>
+
+<p>Table: <code>Examinations</code></p>
+
+<pre>+--------------+---------+
+| Column Name  | Type    |
++--------------+---------+
+| student_id   | int     |
+| subject_name | varchar |
++--------------+---------+
+There is no primary key (column with unique values) for this table. It may contain duplicates.
+Each student from the Students table takes every course from the Subjects table.
+Each row of this table indicates that a student with ID student_id attended the exam of subject_name.
+</pre>
+
+<p>&nbsp;</p>
+
+<p>Write a solution to find the number of times each student attended each exam.</p>
+
+<p>Return the result table ordered by <code>student_id</code> and <code>subject_name</code>.</p>
+
+<p>The result format is in the following example.</p>
+
+<p>&nbsp;</p>
+<p><strong class="example">Example 1:</strong></p>
+
+<pre><strong>Input:</strong> 
+Students table:
++------------+--------------+
+| student_id | student_name |
++------------+--------------+
+| 1          | Alice        |
+| 2          | Bob          |
+| 13         | John         |
+| 6          | Alex         |
++------------+--------------+
+Subjects table:
++--------------+
+| subject_name |
++--------------+
+| Math         |
+| Physics      |
+| Programming  |
++--------------+
+Examinations table:
++------------+--------------+
+| student_id | subject_name |
++------------+--------------+
+| 1          | Math         |
+| 1          | Physics      |
+| 1          | Programming  |
+| 2          | Programming  |
+| 1          | Physics      |
+| 1          | Math         |
+| 13         | Math         |
+| 13         | Programming  |
+| 13         | Physics      |
+| 2          | Math         |
+| 1          | Math         |
++------------+--------------+
+<strong>Output:</strong> 
++------------+--------------+--------------+----------------+
+| student_id | student_name | subject_name | attended_exams |
++------------+--------------+--------------+----------------+
+| 1          | Alice        | Math         | 3              |
+| 1          | Alice        | Physics      | 2              |
+| 1          | Alice        | Programming  | 1              |
+| 2          | Bob          | Math         | 1              |
+| 2          | Bob          | Physics      | 0              |
+| 2          | Bob          | Programming  | 1              |
+| 6          | Alex         | Math         | 0              |
+| 6          | Alex         | Physics      | 0              |
+| 6          | Alex         | Programming  | 0              |
+| 13         | John         | Math         | 1              |
+| 13         | John         | Physics      | 1              |
+| 13         | John         | Programming  | 1              |
++------------+--------------+--------------+----------------+
+<strong>Explanation:</strong> 
+The result table should contain all students and all subjects.
+Alice attended the Math exam 3 times, the Physics exam 2 times, and the Programming exam 1 time.
+Bob attended the Math exam 1 time, the Programming exam 1 time, and did not attend the Physics exam.
+Alex did not attend any exams.
+John attended the Math exam 1 time, the Physics exam 1 time, and the Programming exam 1 time.
+</pre>
+</div>