未定义的索引：做IF和Elseif

Question

I have a code that insert data into a database with php mysqli getting Undefined index: do on both IF and Elseif line. The insert form works but how do i get the errors to get away? (this is just a part of the code hope you can help)

IF($_GET['do']=='sparatid' ){
   $datum=$_POST['datum'];
   $info=$_POST['info'];
   $color=$_POST['color'];
   $uppdatera = "UPDATE narvaro SET info = '{$info}', color = '{$color}' WHERE datum = '{$datum}'";
   $res = mysqli_query($con, $uppdatera) or die("SQL: Gick ej att uppdatera informationen $uppdatera <br>".mysql_error());
}


ElseIF($_GET['do']=='nytid'){
$datum=$_POST['datum'];
$info=$_POST['info'];
$color=$_POST['color'];
$sql = "insert into narvaro (fornamn, efternamn, datum, info, narvaro_id, pos, color) SELECT (fornamn), (efternamn), '$datum', (info), (narvaro_id), (pos), '$color' FROM narvaro WHERE datum ='2018-02-28'";
$results = mysqli_query($con, $sql);

}

Answer 1

Undefined index:

If the parameter dohas not been sent along with the request you will get the notice undefined index if you are trying to access it with $_GET['do']. To fix this you would have to check if the index do has been set with isset($_GET['do']).

Unexpected elseif:

In the code you provided the elseif should not throw an error, although you should write it all lowercase. If you are interested please have a look at the PHP documentation for else if.

The working code example:

<?php

    // Display all errors
    error_reporting(E_ALL);
    ini_set('display_errors', 1);

    // Check if 'do' has actually been set
    if (isset($_GET['do'])) {
        if ($_GET['do']=='sparatid' ) {
            $datum=$_POST['datum'];
            $info=$_POST['info'];
            $color=$_POST['color'];
            $uppdatera = "UPDATE narvaro SET info = '{$info}', color = '{$color}' WHERE datum = '{$datum}'";
            $res = mysqli_query($con, $uppdatera) or die("SQL: Gick ej att uppdatera informationen $uppdatera <br>".mysql_error());
        } else if ($_GET['do']=='nytid') {
            $datum=$_POST['datum'];
            $info=$_POST['info'];
            $color=$_POST['color'];
            $sql = "insert into narvaro (fornamn, efternamn, datum, info, narvaro_id, pos, color) SELECT (fornamn), (efternamn), '$datum', (info), (narvaro_id), (pos), '$color' FROM narvaro WHERE datum ='2018-02-28'";
            $results = mysqli_query($con, $sql);
        }
    }