Sending Multiple Select to MySQL in PHP - php

Question

I am trying to upload two sets of multiple selects into a MariaDB database (many to many relationship intermediate table). The selected options are being properly uploaded but the code is also sending in the last entry from both selects. In other words, if I select options 1 and 4 from the first select that contains 10 options, and I select 5 and 12 from the second select that contains 15 options, instead of populating 4 entries (1 and 5, 1 and 12, 4 and 5, 4 and 12) it is populating 9 options (the four that are supposed to be there plus 1 and 15, 4 and 15, 10 and 15, etc). Each select is populated from the two tables. Below is the code.
<?php
include ("connect_movieDB.php");
connectDB();
$display_block = "<h1>Populate Movie-Actor table</h1></br>
<p>Select a movie and select the actors</p>";
$get_movie_sql = "SELECT id as movie_id, movie_title, movie_releasedate FROM movies ORDER BY movie_title asc";
$get_movie_results = mysqli_query($mysqli, $get_movie_sql) or die(mysqli_error($mysqli));
$get_actor_sql = "SELECT id as actor_id, CONCAT_WS(' ', f_name, l_name) AS display_name FROM actors ORDER BY l_name asc, f_name asc";
$get_actor_results = mysqli_query($mysqli, $get_actor_sql) or die(mysqli_error($mysqli));
if ((mysqli_num_rows($get_movie_results) < 1) || (mysqli_num_rows($get_actor_results) < 1)) {
$display_block .= "<p><em>Did we forget to populate the database?</em></p>";
} else {
$display_block .= "
<form method=\"post\" action=\"".$_SERVER['PHP_SELF']."\">
<p><label for=\"sel_movie\">Select a movie:</label></br>
<select id=\"sel_movie\" size=\"10\" name=\"sel_movie[]\" required=\"required\" multiple=\"multiple\">
<option value=\"\">--Select a Movie--</option>";
while ($movies = mysqli_fetch_array($get_movie_results)) {
$movieid = $movies['movie_id'];
$display_movie_title = stripslashes($movies['movie_title']);
$display_moviedate = stripslashes($movies['movie_releasedate']);
$display_block .="<option value=\"".$movieid."\">".$display_movie_title." - (".$display_moviedate.")</option>";
}
$display_block .= "
</select></br>
<p><label for \"sel_actor\">Select the actors in the movie:</label></br>
<select id=\"sel_actor\" size=\"10\" name=\"sel_actor[]\" required=\"required\" multiple=\"multiple\">
<option value=\"\">--Select actor(s)--</option>";
while ($actors = mysqli_fetch_array($get_actor_results)) {
$actorid = $actors['actor_id'];
$display_actor_name = stripslashes($actors['display_name']);
$display_block .="<option value=\"".$actorid."\">".$display_actor_name."</option>";
}
$display_block .="
</select></p>
<input type=\"hidden\" name=\"sel_movie[]\" value='".$movieid."'/>
<input type=\"hidden\" name=\"sel_actor[]\" value='".$actorid."'/>
<button = type=\"submit\" name=\"submit\" value=\"addtotable\">Add Relationship</button>
<p>Return to the main menu</p>
</form>";
}
if ($_POST) {
if ((isset($_POST['sel_movie'])=="") || (isset($_POST['sel_actor'])=="")){
header("location: addto_ma_table.php");
exit;
}
connectDB();
$movie_array = $_POST['sel_movie'];
$actor_array = $_POST['sel_actor'];
foreach($movie_array as $m) {
foreach($actor_array as $a) {
$check_sql = "SELECT movie_id, actor_id FROM movie_actor WHERE movie_id ='".$m."' AND actor_id ='".$a."'";
$check_results = mysqli_query($mysqli, $check_sql) or die(mysqli_error($mysqli));
$add_info_sql = "INSERT INTO movie_actor (movie_id, actor_id) VALUES ('".$m."', '".$a."')";
$add_info_results = mysqli_query($mysqli, $add_info_sql) or die(mysqli_error($mysqli));
header("Location: addto_ma_table.php");
}
} mysqli_close($mysqli);
}
?>
Thanks for any assistance

Answer 1

There are two hidden inputs after you close the second select. They are adding the last values from your queries to the post arrays. Remove those and it should work better.