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Mysql Where
Posted on: January 17, 2009 By Deepak Kumar

Mysql Where returns only those records from table which are specified in the WHERE Clause.

Mysql Where

Mysql Where returns only those records from table which are specified in the WHERE Clause. The Where Clause restricts the select query and shows you only the records specified in the Where Clause conditions.

Understand with Example

The Tutorial illustrate an example from 'Mysql Where', To understand an example we show you a demonstrative example that uses Where Clauses. The CREATE TABLE keyword creates a table 'Mytable' with required fieldnames and datatypes respectively.

Query for creating table:

mysql> CREATE TABLE MyTable (
    ->              Empid int(10),
    ->              Empname varchar(60)
    ->              Salary int(90)
    ->            );
Query OK, 0 rows affected (0.13 sec)

Query for inserting data in table:

The Query insert into adds the records or rows value to the table 'MyTable'.

mysql>   insert into MyTable values(01,'Girish','20000');
Query OK, 1 row affected (0.02 sec)

mysql>     insert into MyTable values(02,'A','21000');
Query OK, 1 row affected (0.01 sec)

mysql>     insert into MyTable values(03,'C','22000');
Query OK, 1 row affected (0.00 sec)

mysql>     insert into MyTable values(04,'V','23000');
Query OK, 1 row affected (0.00 sec)

mysql>     insert into MyTable values(05,'B','24000');
Query OK, 1 row affected (0.00 sec)

mysql>     insert into MyTable values(06,'E','25000');
Query OK, 1 row affected (0.00 sec)

mysql>     insert into MyTable values(07,'Q','26000');
Query OK, 1 row affected (0.01 sec)

mysql>     insert into MyTable values(08,'W','27000');
Query OK, 1 row affected (0.01 sec)

mysql>     insert into MyTable values(09,'AS','28000');
Query OK, 1 row affected (0.00 sec)`

Query to view data inserted in table:

mysql> select * from mytable;
+-------+---------+--------+
| Empid | Empname | Salary |
+-------+---------+--------+
| 1     | Girish  | 20000  |
| 2     | A       | 21000  |
| 3     | C       | 22000  |
| 4     | V       | 23000  |
| 5     | B       | 24000  |
| 6     | E       | 25000  |
| 7     | Q       | 26000  |
| 8     | W       | 27000  |
| 9     | AS      | 28000  |
+-------+---------+--------+
9 rows in set (0.01 sec)

Query for using where clause:

The Query return only those records from 'mytable' that are specified in Where Clause. In this example the table returns records whose salary is 2000.

mysql> select empname from mytable where salary=20000;

Output:-

+---------+
| empname |
+---------+
| Girish  |
+---------+
1 row in set (0.03 sec)