MySQL Where Clause in PHP
If we want to select only specific column in table then we
can use the WHERE Keyword in SQL. We have seen SELECT Command to fetch data
from MySQL table. We can use a conditional clause called WHERE Clause to filter
out results. Using WHERE Clause we can specify
a selection criteria to select a specific record from a table.
Syntax: Select
field1, field2, field3 from table_name where conditon1 or condition 2
The WHERE clause works like an if condition in any
programming language. This clause is used to compare given value with the field
value with the field value available in MySQL Table There are some operator
used in WHERE clause.
Assume field A holds 20 and field B holds 30.
Operator
|
Description
|
Example
|
=
|
Checks both value they are equal or not equal
|
(A=B)
is
not true
|
!=
|
Checks both value they are equal or not equal if they not
equal then condition is true
|
(A!=B)
is
true
|
>
|
Checks if the value of left operand is greater then right
operand if yes then condition is true
|
(A>B)
is
not true
|
<
|
Checks if the value of left operand is less then right
operand if yes then condition is true
|
(A<B
) is
not true
|
>=
|
Checks if the value of left operand is greater then or
equal to the right operand if yes then condition is true
|
(A>=B) is
not true
|
<=
|
Checks if the value of left operand is less then or equal
to right operand if yes then condition is true
|
(A<=B)
is
true
|
Example:
<?php
$con=mysql_connect(“localhost”, “deep “, 12345);
if (!$con)
{
die(“could not be connect the database” . mysql_error());
}
echo “ connected successfully “;
mysql_select_db ( “student”);
$sql = ”select stu_id, stu_name, stu_class from student1
where stu_id=10;
$retrive =mysql_query ($sql, $con );
If (!$retrive)
{
die (“could not be connect”);
}
While ($row = mysql_fetch_array ($retrive))
{
echo “ Student id is
: {$row [‘stu_id’] } <br>”.
“ Student Name is : {$row [‘stu_name’] } <br>”.
“ Student Class is : {$row [‘stu_class’] } <br>” ;
}
mysql_close ($con);
?>
