My variable iz zero but IF doesn't recognize it?

Question

$check1 = mysqli_query($conn, "select * from Sailors where Name='$habboname'");
$check2 = mysqli_query($conn, "select * from Sailors where Position='$position'");
$num_rows = mysqli_num_rows($check1);
$num_rows2 = mysqli_num_rows($check2);
if ($num_rows > 0)  {
    echo "This user (<b>" . $habboname . "</b>) is already in our database.";
    exit();
} else {
    if ($num_row2 = 0){
    $sql =  "INSERT INTO Sailors (ID, Name, Joined, Rank, Billet, Position, Status, Promoter, Reason, Promo_Date)
    VALUES ('', '$habboname', '$date', '$rank', '$billet', '$position', 'Active', '$promoter', '$reason', '$date')";

    if ($conn->query($sql) === TRUE) {
        header("Location: useradded.php");
    } else {
        echo "Error: " . $sql . "<br>" . $conn->error;
    }
} else {
        echo $num_row2;
    }

It will always echo, even if the variable IS 0. I am really confused. If you know what the issue is, please let me know. Thanks :)

score 3 · Accepted Answer · answered Sep 01 '17 at 23:22

3

You are checking the assignment:

if ($num_row2 = 0){

While you should actually check for equality:

if ($num_row2 == 0){

answered Sep 01 '17 at 23:22

Dekel

60,707
10
101
129

1

Ohhh! Thank you loads, I don't know how I missed that. – xkore2 Sep 01 '17 at 23:23
1

You are welcome :) Will appreciate if you mark the answer as correct when possible. – Dekel Sep 01 '17 at 23:24
1

I have to wait 15 minutes, will do. :) – xkore2 Sep 01 '17 at 23:28
1

When doing equality checks, it's better to use `===`. See [here](https://stackoverflow.com/questions/2063480/the-3-different-equals) – ishegg Sep 01 '17 at 23:42
1

@ishegg I agree when you don't know the type of the result, but that's not the case here since `mysqli_num_rows` will return the number of the results (0 if no results found). – Dekel Sep 01 '17 at 23:44

Alive to die - Anant · Answer 2 · 2017-09-01T23:43:45.857

2

if ($num_row2 = 0){

is not comparison its actually assignment.

So Convert it to:-

if ($num_row2 == 0){ //comparison

Or

if ($num_row2 === 0){ //comparison

edited Sep 01 '17 at 23:43

answered Sep 01 '17 at 23:23

Alive to die - Anant

70,531
10
51
98

score 2 · Answer 3 · answered Sep 01 '17 at 23:32

2

 if ($num_row2 = 0){

try to set $num_row2 = 0. Always it can. You can use this ways:

 if ($num_row2 == 0){

or expert way:

 if (!$num_row2){

Best regards.

answered Sep 01 '17 at 23:32

Amin Djawadi

25
1
6

score 1 · Answer 4 · answered Sep 01 '17 at 23:40

One way you can avoid making an assignment error in PHP when your real intention is to do a comparison is to train yourself to code as follows:

if (0 == $num_row2)

It may be feel a little awkward at first, but it really can help in avoiding the assignment operator when one intends a comparison based on equality and of course the same technique is good for a comparison based on identity.

My variable iz zero but IF doesn't recognize it?

4 Answers4