Chapter 7, Problem 15P

Program Plan Intro

“COUNT()” function:

In SQL, the “COUNT()” function will return the total number of rows in the table with satisfying the criteria mentioned in the “WHERE” clause.

SUM function:

The “SUM” function is used to add the value and then return the sum of the expression in a “SELECT” statement.

Syntax:

SELECT SUM (exp) FROM table_Name [WHERE condition];

AVERAGE function:

The “AVERAGE” function is used to the return the average of the expression in a “SELECT” statement.

Syntax:

SELECT AVG (exp) FROM table_Name [WHERE condition];

GROUP BY Clause:

The GROUP BY clause is used to group the result of a SELECT statement done on a table where the tuple values are similar for more than one column

Syntax:

SELECT expression1, expression2, expression_n, aggregate_function (expression)FROM table_name WHERE conditions GROUP BY expression1, expression2, expression_n;

INNER JOIN keyword:

“INNER JOIN” keyword is used to select all the matching records of both the table.

Syntax:

SELECT col_Name FROM table_Name1 INNER JOIN table_Name2 ON table_Name1.col_Name = table_Name2.col_Name;