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The WHERE Clause is used when you want to retrieve specific information from a table excluding other irrelevant data. For example, when you want to see the information about students in class 10th only then you do need the information about the students in other class. Retrieving information about all the students would increase the processing time for the query.

So SQL offers a feature called WHERE clause, which we can use to restrict the data that is retrieved. The condition you provide in the WHERE clause filters the rows retrieved from the table and gives you only those rows which you expected to see. WHERE clause can be used along with SELECT, DELETE, UPDATE statements.


WHERE {column or expression} comparison-operator value
Syntax for a WHERE clause with Select statement is:
SELECT column_list FROM table-name WHERE condition;
  • column or expression - Is the column of a table or a expression
  • comparison-operator - operators like = < > etc.
  • value - Any user value or a column name for comparison

For Example: To find the name of a student with id 100, the query would be like:

SELECT first_name, last_name FROM student_details WHERE id = 100;

How to use expressions in the WHERE Clause?

Expressions can also be used in the WHERE clause of the SELECT statement.

For example: Lets consider the employee table. If you want to display employee name, current salary, and a 20% increase in the salary for only those products where the percentage increase in salary is greater than 30000, the SELECT statement can be written as shown below

SELECT name, salary, salary*1.2 AS new_salary FROM
WHERE salary*1.2 > 30000;
Name Salary New_salary
Mohan 35000 370000
Vijendra 30000 360000