SQL where clause

The select statement will retrieve all the rows of the table.
If you need to retrieve the data based on some condition we will have to use the where clause.
The where clause is used to filter the records based on the condition provided.

Syntax

select column_1, column_2, ...  
from table_name  
where condition;

Let's assume that we have a table employee with the following data.

Example for where clause

select * from employee where location = 'India';

Output

We can perform multiple operation in where clause.

Lets see few queries using the above operation.

Example 1

select * from employee where age > 25;

This will retrieve the employees whose age is greater than 25. The output will be as below.

Example 2

select * from employee where role <> 'Manager';

This will return the employees whose role is not Manager.

Output

Example 3

select * from employee
WHERE age BETWEEN 21 AND 25;

This will return the records of the employee whose age is between 21 and 25.

Output

Example 4

select * from employee where name like '%lin%';

This will return the records of the employee whose name contains the pattern lin in their name.

Output

We can also use this like query with following pattern.
'xx%' - Start's with xx.
'%x' - End's with x.
'%xx%' - Finds any value that contains xx pattern in it.
'x%' - Find the value that have x in the second position.
'x%' - Finds any values that start with x and are at least 2 characters in length.
'a%z' - Finds any values that start with a and ends with z.

Example 5

select * from employee where location in ('India','USA');

This will retrieve all the employees in India and USA location.

Output