i have a simple code to input data to my database using prepare and bind_param
there is no error but my data are not inputted into database
$stmt1 = $mysqli -> prepare ("INSERT INTO equipment(eqp_type, eqp_name, eqp_qty, eqp_usd, $eqp_idr) VALUES (?,?,?,?,?)");
$stmt1->bind_param('sssss',$eqp_type, $eqp_name, $eqp_qty, $eqp_usd, eqp_idr);
$eqp_type = 'BUC';
$eqp_name = 'BUC test';
$eqp_qty = '1';
$eqp_usd = '0';
$eqp_idr = '0';
$stmt1->execute();
is there any idea why there is no error but my data are not inputted into database ?