Chapter 7, Problem 22P

Program Plan Intro

WHERE Statement:

“WHERE” statement is used limit the number of rows. For example: Consider a table “FTable” that has two columns named “FruitName” and “Color”. “WHERE” clause is used when there is a need to display the entire FruitName whose color is Red.

SELECT * FROM FTable WHERE color = 'red';

When the above statement is executed, red colored fruits get displayed.

Grouping Rows:

SQL contains “GROUP BY” clause in order to group rows by common data. Though it is very powerful feature, it is hard to understand.

Syntax:

 SELECT column_Name1 FROM table_Name GROUP BY column_Name2;

Example: Consider a table “student” contains two columns “student_Name” and “Department”. “GROUP BY” clause is used when there is a need to get the number of students from each department. The query for this scenario is given as follows.

SELECT department, COUNT (department) FROM student GROUP BY department;

When the above query is executed, number of students from each department will be displayed.