当我用mysqli命中提交时执行多查询

Question

I'm just learning Mysql/PHP and I'm trying to execute a multi query using msqli. I have read through several tutorials, and tried to apply them, but I cannot get this working... hope someone can help me.

Dont mind my messy code, will clean later!!!

Code :

else if (isset($_POST['btnSlaOpInGs'])) {
        $id=$_POST['id'];
        $uitgeleend=$_POST['uitgeleend'];
        $nr=$_POST['nr'];
        $model=$_POST['model'];
        $serienummer=$_POST['serienummer'];
        $capaciteit=$_POST['capaciteit'];
        $uptodate=$_POST['uptodate'];
        $persoon=$_POST['persoon'];
        $datumuitgeleend=$_POST['datumuitgeleend'];
        $datumretour=$_POST['datumretour'];
        $opmerking=$_POST['opmerking'];
        $sql="UPDATE ipads SET nr='$nr', model='$model', serienummer='$serienummer', capaciteit='$capaciteit', uptodate='$uptodate', persoon='$persoon', datumuitgeleend='$datumuitgeleend', datumretour='$datumretour', opmerking='$opmerking' WHERE id='$id';";
        $sql.="INSERT INTO geschiedenis (SELECT * FROM ipads WHERE id='$id');";
        $sql.="UPDATE ipads SET uitgeleend='Nee', persoon='', datumuitgeleend='', datumretour='', opmerking='' WHERE id='$id';";
        mysqli_multi_query($db, $sql);
        header("location:index.php");
}

Form :

<form id="gegevensForm" class="col-xs-4" form method="POST" action="ipad-edit.php">
    <input type="hidden" name="id" value="<?php echo $id?>">
    <div class="form-group">
        <label>Uitgeleend</label>
        <select class="form-control" name="uitgeleend"/>
            <option value="Ja" <?php if($uitgeleend == "Ja") echo "selected";?>>Ja</option>
            <option value="Nee" <?php if($uitgeleend== "Nee") echo "selected";?>>Nee</option>
        </select>
    </div>

    <div class="form-group">
        <label>Nr</label>
        <input type="text" class="form-control" name="nr" value="<?php echo $nr ?>" />
    </div>

    <div class="form-group">
        <label>Model</label>
        <input type="text" class="form-control" name="model" value="<?php echo $model ?>" />
    </div>

    <div class="form-group">
        <label>Serienummer</label>
        <input type="text" class="form-control" name="serienummer" value="<?php echo $serienummer ?>" />
    </div>
    
    <div class="form-group">
        <label>Capaciteit</label>
         <input type="text" class="form-control" name="capaciteit" value="<?php echo $capaciteit ?>" />
    </div>
   
    <div class="form-group">
        <label>Up-to-Date</label>
        <select class="form-control" name="uptodate"/>
            <option value="Ja" <?php if($uptodate == "Ja") echo "selected";?>>Ja</option>
            <option value="Nee" <?php if($uptodate == "Nee") echo "selected";?>>Nee</option>
        </select>
    </div>

    <div class="form-group">
        <label>Persoon</label>
        <input type="text" class="form-control" name="persoon" value="<?php echo $persoon ?>" />
    </div>
    
    <div class="form-group">
        <label>Datum uitgeleend</label>
        <input type="text" id="datepicker" class="form-control" name="datumuitgeleend" value="<?php echo $datumuitgeleend ?>" />
    </div>
    
    <div class="form-group">
        <label>Datum retour</label>
        <input type="text" id="datepicker1" class="form-control" name="datumretour" value="<?php echo $datumretour ?>" />
    </div>
    
    <div class="form-group">
        <label for="comment">Opmerking</label>
        <textarea class="form-control" rows="5" id="comment" name="opmerking" /><?php echo $opmerking ?></textarea>
    </div>

    <button class="btn btn-primary pull-right" name="btnSlaOp" input type="submit"><i class="fa fa-save"></i> Opslaan</button>
    
    <a href="overzicht-ipads.php"><input type="button" name="btnCancel" value="Annuleer" class="btn btn-primary pull-left"></a>
    
    <button class="btn btn-primary pull-middle" name="btnSlaOpInGs" type="submit"><i class="fa fa-save"></i> Opslaan & Archiveren</button>
    
    <?php
        include('../includes/get_footer.php');
    ?>
</form>

</div>

Answer 1

1. DO NOT USE multi_query. this function has a very special purpose that doesn't fit for your case. run your queries through separate calls.
2. Use prepared statements.
3. Use PDO, especially if you are only learning PHP.

The code should be

$sql="UPDATE ipads SET nr=?, model=?, serienummer=?, capaciteit=?, uptodate=?, persoon=?, datumuitgeleend=?, datumretour=?, opmerking=? WHERE id=?";
$pdo->prepare($sql)->execute([$nr,$model,$serienummer,$capaciteit,$uptodate,$persoon,$datumuitgeleend,$datumretour,$opmerking,$id]);

$sql="INSERT INTO geschiedenis (SELECT * FROM ipads WHERE id=?)";
$pdo->prepare($sql)->execute([$id]);

$sql ="UPDATE ipads SET uitgeleend='Nee', persoon='', datumuitgeleend='', datumretour='', opmerking='' WHERE id=?";
$pdo->prepare($sql)->execute([$id]);

though I don't quite understand what all this stuff is intended to do. All these settings and resettings of same values looks like a total mess.