SQL Where Clause With examples

SQL WHERE Clause

• To limit the number of rows use the WHERE clause.
• The WHERE clause filters for rows that meet certain criteria.
• WHERE is followed by a condition that returns either true or false.
• WHERE is used with SELECT, UPDATE, and DELETE.

The SQL WHERE syntax

A WHERE clause with a SELECT statement:

1. SELECT column-names FROM table-name WHERE condition

A WHERE clause with an UPDATE statement:

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

A WHERE clause with a DELETE statement:

DELETE table-name WHERE condition

 

SQL WHERE Clause Examples

1) with a select statement

mysql> select name from person where age=26;

+-----------------+
| name            |
+-----------------+
| shantanu biswas |
| sudip saha      |
+-----------------+
2 rows in set (0.00 sec)

2) with an update statement

mysql> update person set sex='M' where age=25;
Query OK, 0 rows affected (0.00 sec)
Rows matched: 1  Changed: 0  Warnings: 0