mysql_fetch_array() expects parameter 1 to be resource (or mysqli_result), boolean given
I am trying to select data from a MySQL table, but I get one of the following error messages:
mysql_fetch_array() expects parameter 1 to be resource, boolean given
or
mysqli_fetch_array() expects parameter 1 to be mysqli_result, boolean given
This is my code:
$username = $_POST['username'];
$password = $_POST['password'];
$result = mysql_query('SELECT * FROM Users WHERE UserName LIKE $username');
while($row = mysql_fetch_array($result))
{
echo $row['FirstName'];
}
1Answer
A query may fail for various reasons in which case both the mysql_* and the mysqli extension will return false from their respective query functions/methods. You need to test for that error condition and handle it accordingly.
Check $result before passing it to mysql_fetch_array. You'll find that it's false because the query failed. See the mysql_query documentation for possible return values and suggestions for how to deal with them.
$username = mysql_real_escape_string($_POST['username']);
$password = $_POST['password'];
$result = mysql_query("SELECT * FROM Users WHERE UserName LIKE '$username'");
if($result === FALSE) {
die(mysql_error()); // TODO: better error handling
}
while($row = mysql_fetch_array($result))
{
echo $row['FirstName'];
}
mysqli extension
procedural style:
$username = mysqli_real_escape_string($mysqli, $_POST['username']);
$result = mysqli_query($mysqli, "SELECT * FROM Users WHERE UserName LIKE '$username'");
// mysqli_query returns false if something went wrong with the query
if($result === FALSE) {
yourErrorHandler(mysqli_error($mysqli));
}
else {
// as of php 5.4 mysqli_result implements Traversable, so you can use it with foreach
foreach( $result as $row ) {
...
oo-style:
$username = $mysqli->escape_string($_POST['username']);
$result = $mysqli->query("SELECT * FROM Users WHERE UserName LIKE '$username'");
if($result === FALSE) {
yourErrorHandler($mysqli->error); // or $mysqli->error_list
}
else {
// as of php 5.4 mysqli_result implements Traversable, so you can use it with foreach
foreach( $result as $row ) {
...
using a prepared statement:
$stmt = $mysqli->prepare('SELECT * FROM Users WHERE UserName LIKE ?');
if ( !$stmt ) {
yourErrorHandler($mysqli->error); // or $mysqli->error_list
}
else if ( !$stmt->bind_param('s', $_POST['username']) ) {
yourErrorHandler($stmt->error); // or $stmt->error_list
}
else if ( !$stmt->execute() ) {
yourErrorHandler($stmt->error); // or $stmt->error_list
}
else {
$result = $stmt->get_result();
// as of php 5.4 mysqli_result implements Traversable, so you can use it with foreach
foreach( $result as $row ) {
...
- answered 8 years ago
- Gul Hafiz
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