Wordpress wpdb->query problems with importing data - mysql

Question

My line of code below is supposed to update a NULL value field with (in this case) a pre-defined value. When i execute my wpdb query however the page gives a 500 error.
$wpdb->query( $wpdb->query( "UPDATE ziekbeter SET healthy= '1994-06-04' WHERE person = 5 AND sick IS NOT NULL AND healthy IS NULL") );
Can someone take a look at the line of code and possibly tell me whats wrong?
The code is being executed on a button click.
A screenshot of my wp table is added.
Person ID and the healthy date are going to be dynamic but for now im keeping it static.
profile.php
<?php
$user_ID = get_current_user_id();
echo $user_ID;
global $wpdb;
if ($wpdb->get_results( "SELECT * FROM ziekbeter WHERE person = $user_ID AND healthy IS NULL"))
{
$row = $wpdb->get_results( "SELECT * FROM ziekbeter WHERE person = $user_ID AND healthy IS NULL");
{
?>
<form action="<?php bloginfo('url'); ?>/wp-content/themes/stk/ziekbeter.php" method="post">
<input type="submit" name="submitBeter" value="Meld mij beter!">
</form>
<?php
}
}
elseif ($wpdb->get_results("SELECT healthy FROM ziekbeter WHERE person = $user_ID AND healthy IS NOT NULL"))
{
$row = $wpdb->get_results( "SELECT * FROM ziekbeter WHERE person = $user_ID AND healthy IS NOT NULL");
{
?>
<form action="<?php bloginfo('url'); ?>/wp-content/themes/stk/ziekbeter.php" method="post">
<input type="submit" name="submitZiek" value="Meld mij ziek!">
</form>
<?php
}
}
else {
?>
<form action="<?php bloginfo('url'); ?>/wp-content/themes/stk/ziekbeter.php" method="post">
<input type="submit" name="submitZiek" value="Meld mij ziek!">
</form>
<?php
}
?>
ziekbeter.php
if(isset($_POST['submitZiek']))
{
/* This function will come after i got the submitBeter working */
}
elseif(isset($_POST['submitBeter']))
{
$wpdb->query( $wpdb->query( "UPDATE ziekbeter SET healthy= '1994-06-04' WHERE person = 5 AND sick IS NOT NULL AND healthy IS NULL") );
echo "submitBeter wordt uitgevoerd";
}
Should i replace the wpdb-> query with an echo the code will execute properly and run the echo without any problems.

Answer 1

Try reworking the logic, something like:
profile.php
<?php
global $wpdb;
$user_ID = get_current_user_id();
echo $user_ID;
//First DB query
$row1 = $wpdb->get_results("SELECT * FROM ziekbeter WHERE person = $user_ID AND healthy IS NULL");
//Second DB query
$row2 = $wpdb->get_results("SELECT healthy FROM ziekbeter WHERE person = $user_ID AND healthy IS NOT NULL");
// I.e. greater than zero draw the HTML form
if (count($row1)>0) {
?>
<form action="<?php esc_url(bloginfo('url')); ?>/wp-content/themes/stk/ziekbeter.php" method="post">
<input type="submit" name="submitBeter" value="Meld mij beter!">
</form>
<?php
}
// Second DB query draw different HTML form
if (count($row2)>0) {
?>
<form action="<?php esc_url(bloginfo('url')); ?>/wp-content/themes/stk/ziekbeter.php" method="post">
<input type="submit" name="submitZiek" value="Meld mij ziek!">
</form>
<?php
}
// Draw third HTML form otherwise
if (!$row1 || !$row2) {
?>
<form action="<?php esc_url(bloginfo('url')); ?>/wp-content/themes/stk/ziekbeter.php" method="post">
<input type="submit" name="submitZiek" value="Meld mij ziek!">
</form>
<?php
}
?>
Now, the other file, do not forget to globalize the $wpdb variable:
ziekbeter.php (EDITED):
<?php
global $wpdb;
if(isset($_POST['submitZiek'])) {
/* This function will come after i got the submitBeter working */
}
if(isset($_POST['submitBeter'])) {
$result = $wpdb->query( "UPDATE ziekbeter SET healthy= '1994-06-04' WHERE person = 5 AND sick IS NOT NULL AND healthy IS NULL");
/*Or, use the native WordPress function:
$result = $wpdb->update( $table, $data, $where, $format = null, $where_format = null ); */
if ($result) echo "submitBeter wordt uitgevoerd";
}
?>

Answer 2

If you're trying to access those files directly, i.e. http://example.com/wp-content/themes/stk/profile.php and http://example.com/wp-content/themes/stk/ziekbeter.php, then you need to include WordPress:
<?php
require_once '../../../wp-load.php';
// rest of profile.php
<?php
require_once '../../../wp-load.php';
// rest of ziekbeter.php