PHP mysqli SELECT查询将不会执行

Question

$dc=fopen("numeu.txt","rb");
$row1=fgets($dc,120);   
$row2=fgets($dc,120);
$row3=fgets($dc,120);

fclose($dc);

$servername="localhost";
$username="root";
$password='';
$database="Stildev";

$conn = new mysqli($servername, $username, $password, $database);

$sql="SELECT poza1,poza2,poza3,poza4,poza5,poza6 FROM postari WHERE utilizator='".$row2."' AND subiect='".$row1."' AND id2='".$row3."'";


$resultat=$conn->query($sql);

echo $resultat->num_rows;

This piece of code returns 0 rows

There is no error and sql query works just fine in MySQL console.

Also i discovered that withought WHERE clause the code works.How you explain that?

Answer 1

Is the password empty on purpose?

Try adding

if ($mysqli->connect_error) {
    die('Connect Error (' . $mysqli->connect_errno . ') '
        . $mysqli->connect_error);
}

Also, according to https://php.net/manual/ro/mysqli.query.php , this may help:

if ($result = $mysqli->query($sql)) {
    echo $result->num_rows;
    /* close result set */
    $result->close();
}

If you are using several result-returning queries, close previous results with ->close();