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
where field_name<=1000
Another Syntax
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
############################
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); ?>