用php将multiselect添加到数据库中

Question

I'm trying to get a input from a multiselect into a database. below is a snippet of the select field in the form I have. I did find the suggestion to [] so I added that. was a big step forward

<select name="project_dicipline[]" data-placeholder="Select uw dicipline(s)" class="chosen-select" multiple style="width:350px;">
     <option value=""></option> 
     <option value="Elektra_LS">Elektra LS</option> 
     <option value="Elektra_MS">Elektra MS</option> 
     <option value="Elektra_OV">Elektra OV</option>
</select>

Below is what I got for reading the info out of the _POST it works fine if I just echo the foreach() line (got it from another post on stackoverflow), but I want to add it in a database, and I'm not sure how to get that done. I could really use some help for that.

$project_dicipline = array();
foreach ($_POST['project_dicipline'] as $project_dicipline)
   $project_dicipline = mysqli_real_escape_string($conn, $project_dicipline);
   echo $project_dicipline;

--edit-- below is the connection to db. That part i know works, because the rest of the form gets validated and added to the form. for that reason i have cut out a lot of the fields out of the query. (all variables have been escaped before the query is run)

    $conn = mysqli_connect($servername, $usernamedb, $passwordDB, $database);
    if (!$conn) 
    {
        die("Connection failed: " . mysqli_connect_error());
    }


    $query = "INSERT INTO projects (project_status, project_name, project_client, project_diciplines)

     VALUES('New', '$project_naam', '$project_plaats', '$project_client_company', '$project_dicipline')";
     mysqli_query($conn, $query);

Answer 1

You need to insert it using the foreach loop if they are to be individual records in the database

$conn = mysqli_connect($servername, $usernamedb, $passwordDB, $database);
if (!$conn) 
{
    die("Connection failed: " . mysqli_connect_error());
}

if ($stmt = mysqli_prepare($conn, "INSERT INTO projects (project_status, project_name, project_client, project_diciplines) VALUES('New', ?, ?, ?, ?)")) {

    $project_dicipline = array();
    foreach ($_POST['project_dicipline'] as $project_dicipline){
         $project_dicipline = mysqli_real_escape_string($conn, $project_dicipline);

         mysqli_stmt_bind_param($stmt, $project_naam, $project_plaats,$project_client_company,$project_dicipline);

         /* execute query */
         mysqli_stmt_execute($stmt);
    }

}

You can read more about mysqli on php.net http://php.net/manual/en/book.mysqli.php and post/loops as well http://php.net/manual/en/control-structures.foreach.php and http://php.net/manual/en/reserved.variables.post.php