Advanced MySQL GROUP BY: Examples of Student Tuition and Grade Management Part 2

Take your MySQL skills to the next level with our advanced GROUP BY tutorial. Learn through practical examples of student tuition and grade management, and discover how to efficiently group, filter, and sort data using this powerful SQL clause.

View More: Advanced MySQL GROUP BY: Examples of Student Tuition and Grade Management Part 1

Coursework

Grouping by Course

Suppose we have a table named coursework with columns id, student_id, course_id, and grade. We want to find out the average grade for each course. We can achieve this using the following query:

SELECT course_id,
       AVG(grade) AS average_grade
FROM coursework
GROUP BY course_id;

In this query, we are using the AVG() function to calculate the average grade for each course. We are selecting the course_id column and the average_grade column. We are grouping the data by the course_id column using the GROUP BY clause.

Grouping by Student

Suppose we have a table named coursework with columns id, student_id, course_id, and grade. We want to find out the average grade for each student across all courses. We can achieve this using the following query:

SELECT student_id,
       AVG(grade) AS average_grade
FROM coursework
GROUP BY student_id;

In this query, we are using the AVG() function to calculate the average grade for each student. We are selecting the student_id column and the average_grade column. We are grouping the data by the student_id column using the GROUP BY clause.

Grouping by Course and Student

Suppose we have a table named coursework with columns id, student_id, course_id, and grade. We want to find out the average grade for each course and student combination. We can achieve this using the following query:

SELECT course_id,
       student_id,
       AVG(grade) AS average_grade
FROM coursework
GROUP BY course_id,
         student_id;

In this query, we are using the AVG() function to calculate the average grade for each course and student combination. We are selecting the course_id, student_id, and average_grade columns. We are grouping the data by the course_id and student_id columns using the GROUP BY clause.

Grouping by Course

Suppose we have a table named coursework with columns id, student_id, course, and grade. We want to find out the average grade for each course. We can achieve this using the following query:

SELECT course,
       AVG(grade) AS avg_grade
FROM coursework
GROUP BY course;

In this query, we are using the AVG() function to calculate the average grade for each course. We are selecting the course column and the avg_grade column. We are grouping the data by the course column using the GROUP BY clause.

Grouping by Course and Semester

Suppose we have a table named coursework with columns id, student_id, course, semester, and grade. We want to find out the average grade for each course and semester combination. We can achieve this using the following query:

SELECT course,
       semester,
       AVG(grade) AS avg_grade
FROM coursework
GROUP BY course,
         semester;

In this query, we are using the AVG() function to calculate the average grade for each course and semester combination. We are selecting the course, semester, and avg_grade columns. We are grouping the data by the course and semester columns using the GROUP BY clause.

Tuition

Grouping by Semester

Suppose we have a table named tuition with columns id, student_id, semester, and amount. We want to find out the total tuition amount for each semester. We can achieve this using the following query:

SELECT semester,
       SUM(amount) AS total_tuition
FROM tuition
GROUP BY semester;

In this query, we are using the SUM() function to calculate the total tuition amount for each semester. We are selecting the semester column and the total_tuition column. We are grouping the data by the semester column using the GROUP BY clause.

Grouping by Student and Semester

Suppose we have a table named tuition with columns id, student_id, semester, and amount. We want to find out the total tuition amount for each student and semester combination. We can achieve this using the following query:

SELECT student_id,
       semester,
       SUM(amount) AS total_tuition
FROM tuition
GROUP BY student_id,
         semester;

In this query, we are using the SUM() function to calculate the total tuition amount for each student and semester combination. We are selecting the student_id, semester, and total_tuition columns. We are grouping the data by the student_id and semester columns using the GROUP BY clause.

Note that in some cases, you may want to include a WHERE clause to filter the data before grouping it. For example, if you only want to include data from a specific semester or a specific course, you can add a WHERE clause to the query to filter the data accordingly. Additionally, when using aggregate functions like COUNT() and AVG(), be aware that they will not count or average NULL values. If you want to include NULL values in your calculations, you can use the IFNULL() function to replace NULL values with a specified value.