Chapter 4, Problem 14CAT

Program Plan Intro

“SELECT” command:

The “SELECT” command is used to retrieve data in a database.

Syntax for selecting values from the table is as follows:

SELECT STUDENT_ID FROM STUDENT;

• The given query is used to display each student ID from “STUDENT” table.

“AVG” function:

• It is the one function of aggregate function.
• The “AVG” function is used to compute the average value in a column.

Example:

The example for “AVG” function is given below:

SELECT AVG(MARK_CREDIT) FROM STUDENT;

The above query is used to display the average of mark credit from “STUDENT” table using “AVG” function.

“GROUP BY” Clause:

• User can group the data using “GROUP BY” clause.
• This clause allows the user to group data on a specific column and then computes statistics when user preferred.

Example:

The example for “GROUP BY” clause is given below:

SELECT CUSTOMER_NAME, SUM(AMOUNT) FROM CUSTOMERS GROUP BY CUSTOMER_NAME;

The above query is used to list the customer name and the sum of amount using “GROUP BY” clause.