php mysql query with hyphen character - php

Question

I have a query problem with hyphen character.
$user = "test-user";
$q = #mysql_query("SELECT id FROM table WHERE user='$user'");
echo mysql_error(); //no error message
test-user record is in table but query result coming empty. Also mysql error message is empty. What is wrong?
EDIT:
Thank you for answers. I apologize to everyone. I found the problem and I see now the problem is not in the query. Problem coming form regex.
if (preg_match("/^[a-z0-9]+$/i", $user)) //dash character not in regex
{
$q = #mysql_query("SELECT id FROM table WHERE user='$user'");
}
I've corrected the problem as follows:
if (preg_match("/^[a-z0-9\-]+$/i", $user)) //added \- to regex for dash
{
$q = #mysql_query("SELECT id FROM table WHERE user='$user'");
}

Answer 1

Just use mysql_real_escape_string to escape the data string.
$user = "test-user";
$user = mysql_real_escape_string($user);
$q = #mysql_query("SELECT id FROM table WHERE user='$user'");
echo mysql_error(); //no error message
But I would also recommend using or die() syntax instead of the #mysql_query you have in place.
$user = "test-user";
$user = mysql_real_escape_string($user);
$q = mysql_query("SELECT id FROM table WHERE user='$user'") or die ("Error: " . mysql_error());

Answer 2

$p = mysql_query("SELECT id FROM table WHERE user='$user'");
if (!$p)
{
die('Could not query:' . mysql_error());
}
else
{
echo mysql_result($p>0);
}
try it

Answer 3

Try this:
$user = "test-user";
$q = mysql_query("SELECT id FROM `table` WHERE user='".$user."'")
or die(mysql_error());//no error message;
Full example with mysqli_:
$host = "";
$user = "";
$password = "";
$database = "";
$user_name_query = "test-user"; // If this value is from a form please read more about sql-injection.
// open connection to database
$link = mysqli_connect($host, $user, $password, $database);
IF (!$link){
echo ("Unable to connect to database!");
}
ELSE {
// SELECT QUERY
$query = "SELECT id FROM `table` WHERE user='".$user_name_query."'";
mysqli_query($link,$query) or die("Query failed");
}
// close connection to database
mysqli_close($link);

Answer 4

Any difference if you change the query to:
$q = mysql_query("SELECT id FROM table WHERE user='".$user."'");
Unless I'm having a very slow Sunday I think you're searching for the literal string $user rather than the variable value.