WHERE Clause is used to filter the record from the table through condition.
Syntax:-
SELECT column(s)
From table_name
WHERE [condition]
Example:- Suppose you have employees table which has 7 records.
+----+------------+-----------+----------------+-----------+
| id | first_name | last_name | email | country |
+----+------------+-----------+----------------+-----------+
| 1 | John | Tailor | john@abc.com | USA |
| 2 | Rom | Tailor | rom@abc.com | USA |
| 3 | Andrew | Symonds | andrew@abc.com | Australia |
| 4 | Miacle | clerk | miacle@abc.com | Australia |
| 5 | Sachin | Tendulkar | sachin@abc.com | India |
| 6 | Virat | Kohli | virat@abc.com | India |
| 7 | rohit | NULL | rohit@abc.com | India |
+----+------------+-----------+----------------+-----------+
Now you want to get the record, which country belongs to India
SELECT * FROM employees WHERE country='India'
Output:-
+----+------------+-----------+----------------+---------+
| id | first_name | last_name | email | country |
+----+------------+-----------+----------------+---------+
| 5 | Sachin | Tendulkar | sachin@abc.com | India |
| 6 | Virat | Kohli | virat@abc.com | India |
| 7 | rohit | NULL | rohit@abc.com | India |
+----+------------+-----------+----------------+---------+
3 rows in set (0.00 sec)