SQL SELECT Statement WHERE | Restricting and Sorting of Data

This tutorial about SQL SELECT Statement WHERE Restricting and Sorting of Data is the continuation of our previous topics entitled Writing Basic SQL Select Statements With Actual Demonstration.

Objectives of SQL SELECT Statement WHERE

In this lesson, you will be able to the following:

• Limit the rows retrieved by a query
• Sort the rows retrieved by a query

Take note: In retrieving data from the database, there are times that you need to restrict data to display. Because Not all the time you are retrieving all records from the database table.

The WHERE clause can compare values in columns, literal values, arithmetic expressions, or functions .

It consist of three Elements

• Column Name
• Comparison condition
• Column name, constant, or list of values

Syntax:

SELECT *|{[DISTINCT] column/expression [alias],...}
FROM TABLE
[WHERE condition(s)];

Important Note: The WHERE clause follows the FROM clause.

For example we have here a sample table named tblsampleemployee:

Using the SQL Statement WHERE Clause Equal to Operator

Now, if we want to display the employee id and employee name of all employee that belongs to IT Department. here’s the sample query below:

SELECT `EMP_ID`,`EMPNAME` 
FROM `tblsampleemployee` 
WHERE `DEPT_NAME` = 'IT'; 

This will give the following result:

Take note: For strings , we always enclose them in single quotes.

Comparison Conditions

The following example, we will perform the other comparison condition operators.

Using WHERE Clause Greater than Operator

Sample Query:

 SELECT `EMP_ID`,`EMPNAME`, SALARY FROM `tblsampleemployee` WHERE `SALARY` > 50000;

Output:

In the SQL Select Statement above, we display the employee id number, employee name together with their salary that is greater than 50000.

Using WHERE Clause Greater than or equal to Operator

Sample Query:

 SELECT `EMP_ID`,`EMPNAME`, SALARY FROM `tblsampleemployee` WHERE `SALARY` >= 50000;

Output:

In the SQL Select Statement above, we display the employee id number, employee name together with their salary that is greater than or equal to 50000.

Using WHERE Clause Less than to Operator

Sample Query:

 SELECT `EMP_ID`,`EMPNAME`, SALARY FROM `tblsampleemployee` WHERE `SALARY` < 50000;

Output:

In the SQL Select Statement above, we display the employee id number, employee name together with their salary that is less than 50000.

Using WHERE Clause Less than or equal to Operator

Sample Query:

 SELECT `EMP_ID`,`EMPNAME`, SALARY FROM `tblsampleemployee` WHERE `SALARY` <= 50000;

Output:

In the above SQL Query, we display the employee id number, employee name together with their salary that is less than or equal to 50000.

Using WHERE Clause Not equal to Operator

Sample Query:

 SELECT `EMP_ID`,`EMPNAME`, SALARY FROM `tblsampleemployee` WHERE `SALARY` <> 50000

Output:

In the above sql statement, we display the employee id number, employee name together with their salary that is Not equal to 50000.

Video Tutorial of SQL Restricting and Sorting Data Using WHERE Clause

Watch the video tutorial here for complete practice with actual demonstration.

For Inquiries

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