H DDD - Aggregate functions (revision)

What are aggregate functions in SQL?

• Functions that perform a calculation on a set of values and return a single value

• Functions that only work on string data types

• Functions that are not supported by SQL

• Functions that perform a calculation on a single value and return a set of values

Which of the following is not an aggregate function in SQL?

• SUM

• NOT

• MAX

• COUNT

What does the AVG function do in SQL?

• Returns the maximum value of a numeric column

• Counts the total number of rows in a table

• Calculates the average value of a numeric column.

• Sorts the values in a column in ascending order

Which aggregate function is used to find the total sum of a numeric column in SQL?

• COUNT()

• SUM()

• AVERAGE()

• MAX()

What is the result of the COUNT function if there are no matching rows in SQL?

• ERROR

• NULL

• 1

• 0

Which aggregate function is used to find the highest value in a set of values in SQL?

• SUM()

• MAX()

• COUNT()

• MIN()

What does the COUNT function do in SQL?

• Returns the number of rows that match a specified condition.

• Returns the sum of all values in a specified column

• Returns the maximum value of a specified column

• Returns the average value of a specified column

Which aggregate function is used to find the lowest value in a set of values in SQL?

• MIN()

• MAX()

• COUNT()

• SUM()

What does the SUM function do in SQL?

• Returns the average of a specific column in a table

• Sorts the values in a specific column in a table

• Counts the number of rows in a specific column in a table

• Calculates the total sum of a specific column in a table