将php切换列值设置为1或0

Question

I'm learning PHP and getting a little frustrated. I have an html form that is sending data to another php page $_POST["id"];.

On a 2nd php page I'm trying have the "available" column in the table either switch to 1 or 0. If it's already 1 go to 0, and if it's 0 go to 1.

I know my code is probably completely wrong and messy but please excuse me as I'm still learning.

if ($row["available"] == 1) {
    //$row["available"] = 0;
    $sql = "UPDATE check_in_out SET available=0 WHERE id='".$_POST["id"]."'";
    if ($conn->query($sql) === TRUE) {
        echo "Record updated successfully";
    } else {
        echo "Error updating record: " . $conn->error;
    }
} else {
    //$row["available"] = 1;
    $sql = "UPDATE check_in_out SET available=1 WHERE id='".$_POST["id"]."'";
    if ($conn->query($sql) === TRUE) {
        echo "Record updated successfully";
    } else {
        echo "Error updating record: " . $conn->error;
    }
}

Answer 1

If you want to toggle the value you can use this:

$sql = "UPDATE check_in_out SET available = (1-available) WHERE id='".$_POST["id"]."'";

or

$sql = "UPDATE check_in_out SET available = IF(available = 0, 1, 0) WHERE id='".$_POST["id"]."'";