Microsoft SQL Server Development for Everyone - SQL SUM Aggregate Function

The video tutorial explains how to use the sum aggregate function in SQL to calculate the total number of credits each student is taking. It begins by outlining the scenario and the need to gather data from multiple tables: enrollments, students, and courses. The tutorial then demonstrates how to construct a query using inner joins to combine data from these tables. It further explains the use of the group by clause to organize data by student and the sum function to aggregate the total credits. The video concludes by encouraging viewers to experiment with the provided script file.

What is the primary purpose of joining the enrollments, students, and courses tables in this scenario?

• To list all courses available in the database

• To find the total number of credits each student is taking

• To determine the enrollment date of each student

• To calculate the average grade of each student

Which columns are essential for generating the output of total credits per student?

• Student ID and Course ID

• Student Age and Course Duration

• Number of Credits and Student Full Name

• Course Name and Enrollment Date

Why is it unnecessary to include the number of credits in the GROUP BY clause when using the SUM function?

• Because the SUM function automatically groups by all columns

• Because the number of credits is not a column in the database

• Because the GROUP BY clause can only include text columns

• Because the SUM function aggregates the values, making grouping by credits redundant

What does the SUM function do in the context of this SQL query?

• It counts the total number of students enrolled

• It multiplies the number of credits by the number of students

• It calculates the average number of credits per student

• It sums up the total credits for each student

What is the role of the enrollments table in this SQL query?

• It tracks which classes each student is enrolled in

• It stores the grades of each student

• It lists all available courses

• It contains the personal details of each student