PHP MYSQL where clause
How to used where clause
I am going to explain the concept of where clause in database. Where clause is used to fetch particular record from the database.
Suppose a compnay database that have store employs record. Consider the query find all the member which salary amount are greater than $10000, this query written as.
Example
SELECT * FROM employ
where salary > 10000
In another word SELECT data from table as per your condition using where clause. There are some query using where clause are following bewlow.
SELECT * FROM employ
where name = john
SELECT * FROM employ
where name = john and salary =20000
Syntax
SELECT * FROM table_name
where field_name<=1000
where field_name<=1000
Another Syntax
SELECT field_name(s)
FROM table_name
where field_name<=1000
FROM table_name
where field_name<=1000
Example of where clause
<?php
$db = @mysql_connect("locahost","root","");
mysql_select_db("my_db1") or die ("database selection failed");
echo "Connected to the database<br>";
$query="SELECT *from student
where id = 2";
$a=mysql_query($query,$db) or die("fail to execute query!!!");
if(! $a )
{
die('Could not get data: ' . mysql_error());
}
echo "############################";
while($row = mysql_fetch_array($a))
{
echo "
id:{$row['id']}";
echo "<br>Name :{$row['name']} <br> ".
"Branch: {$row['branch']} <br> ";
}
echo "############################";
echo"<br>Query Fetched";
mysql_close($db);
?>
Output
Connected to the database
############################
id:2
Name :xyz
Branch: ma
############################
Query Fetched
############################
id:2
Name :xyz
Branch: ma
############################
Query Fetched
Another example of where clause
<?php
$user = "root";
$pwd = "";
$host = "localhost";
$db = @mysql_connect($host,$user,$pwd);
mysql_select_db("my_db1");
$query="SELECT *from student
where id = 2 or branch='cse' ";
$a=mysql_query($query,$db);
if(! $a )
{
die('Could not get data: ' . mysql_error());
}
echo "############################";
while($row = mysql_fetch_array($a))
{
echo "
id:{$row['id']}";
echo "<br>Name :{$row['name']} <br> ".
"Branch: {$row['branch']} <br> ";
}
echo "############################";
mysql_close($db);
?>
