The WHERE Clause Syntax

The WHERE clause is optional and can be added to any SELECT statement, usually after the FROM clause, as follows:

SELECT [COLUMNS LIST] 
FROM [TABLE NAME]
WHERE [CONDITION]
ORDER BY [COLUMN NAME] [ASC|DESC]

As you can see in the highlighted line, this statement starts with the WHERE keyword followed by a condition.

Conditions in SQL are logical operators that can be used for comparison. Condition operators are listed in the following table:

Figure 5.3: Conditional operators in SQL

These operators can be used to compare two fields/values to achieve the desired results.

Note

The compared fields or values must be of the same data type for the statement to be successful.

A simple implementation of a WHERE clause is as follows:

USE studentdemo; 
SELECT *
FROM Student;

The sample Student table looks like this:

Figure 5.4: Sample student table

Using the Student table of the StudentDemo database...