Select problem using php and mysql

Question

I’m new with the development in php and was seeing some examples of select in a table in mysql on the net, but no successful execution.

The code is as follows::

$conexao = mysql_connect(DB_HOST, DB_USER, DB_PASSWORD) or die (mysql_error());
mysql_select_db(DB_NAME, $conexao) or die (mysql_error());  
// CONNECTION ------------------------------------------------------------------


$query = "SELECT * FROM formcontato";
$result = mysql_query($query);    

while($fetch = mysql_fetch_row($result)){
    echo $fetch[0];
}

When the code is executed, it returns the error:

Warning: mysql_fetch_row() expects Parameter 1 to be Resource, Boolean Given in select.php on line 13

What’s wrong with the code above?