How to use SQL WHERE Condition with Example?

A SQL WHERE Condition  statement only affect rows that meet mentioned criteria and the criteria are expressed in the form of predicates. WHERE clauses are not mandatory clauses of SQL  but can be used to limit the number of rows affected by a  structured query language (SQL), or returned by a query. the main purpose of SQL WHERE clause is used to extract only those Record from a SQL statement, like as INSERT, SELECT, DELETE  or UPDATE,  statement.

The SQL WHERE Condition

• SQL WHERE Clause with SELECT query.

SELECT column-names
  FROM table-name
 WHERE condition

• WHERE Clause with an UPDATE query.

UPDATE table-name
   SET column-name = value
 WHERE condition

• SQL WHERE Condition with a DELETE query

DELETE table-name
 WHERE condition

Example for SQL WHERE Clause

SELECT Id, FirstName, LastName, City, Gender
  FROM Employee
 WHERE City = 'New Delhi'

Example for SQL WHERE Clause with an Updates Statement.

UPDATE Supplier
   SET City = 'New Delhi'
 WHERE Name = 'John'

Example for SQL WHERE Clause with DELETE Statement 

>

DELETE FROM Product
 WHERE UnitPrice > 50

Resource
w3school