Variables in Mysql Query - php

Question

I am writing a PHP script in which i need to run a MySQL query. I opened the data connection and all such pleasantries are working fine. My only doubt is regarding the syntax of the following query, since it is not working. I have a php variable $post_id against which I am selecting from the database.
$query1="SELECT needer FROM needer_blood WHERE value_id='$post_id'";
$result=mysql_query($query);
$req_id=$result[0];

Answer 1

You are not fetching the result.
So try this
<?php
$query1="SELECT needer FROM needer_blood WHERE value_id='$post_id'";
$result=mysql_query($query);
while($row= mysql_fetch_array($result))
{
echo $row['needer'];//You can display your result like this.
}
Also mysql is depricated learn Mysqli or PDO.
For Mysqli function check this link http://php.net/manual/en/book.mysqli.php
For PDO function check this link http://php.net/manual/en/book.pdo.php

Answer 2

try this one, its better approach if you user SQL INJECTION
<?php
$query1="SELECT needer FROM needer_blood WHERE value_id='".mysql_real_escape_string($post_id)."'";
$result=mysql_query($query) or die(mysql_error()); // die only used in development , remove when you live this
$data = mysql_fetch_array($result) or die(mysql_error());
echo $req_id = $data['needer']; // $req_id = $data[0];
?>

Answer 3

Firstly, notice that your query variable is called $query1 and your mysql_query is using a variable called $query (variable mismatch?).
You can use mysql_fetch_assoc() to get an associative array from your query.
Using the following code should work, though you should do some checking to make sure that the $result[0] exists.
// Query String
$query1="SELECT needer FROM needer_blood WHERE value_id='$post_id'";
// Run the query
$result=mysql_query($query1) or die(mysql_error());
// Fetch Associative Array
$rows=mysql_fetch_assoc($result);
// Get result [0]: this could result in an error if your query result is empty.
$req_id=$rows[0];
Also, as others have pointed out, mysql is deprecated and you should update to MySQLi or PDO_MySQL if your server supports it. If not, change servers.
Also, as others pointed out, you should watch out for SQL injection. This StackOverflow answer adresses the issue well.