I'm struggling with Wordpress and Advanced Custom Fields

Question

I've got some PHP code which I'm using in a WordPress website. Here's the code:

<h3>Case Studies</h3>

<?php 
    $the_query = new WP_Query(array(
        'post_type'         => 'post',  
        'posts_per_page'    => -1,
        'cat'               => 3,
        'meta_key'          => 'sector',
        'orderby'           => 'meta_value', 
        'order'             => 'ASC'
    ));

if( $the_query->have_posts() ):
    while( $the_query->have_posts() ) : $the_query->the_post(); ?>

    <a href="<?php echo get_permalink(); ?>">
        <h1><?php the_field('client_name'); ?></h1><p><?php the_field('sector'); ?></p>
        <span style="background-image:url(<?php $url = wp_get_attachment_url( get_post_thumbnail_id($post->ID) ); echo $url; ?>)"></span>
    </a>

<?php endwhile; endif; ?>

<h3>Other Clients</h3>

<?php if( have_rows('clients') ):
    while ( have_rows('clients') ) : the_row(); ?>

        <a>
            <h1><?php the_sub_field('client'); ?></h1><p><?php the_sub_field('sector'); ?></p>
            <span></span>
        </a>

<?php endwhile; endif; ?>

So - at the top, we've got "Case Studies" and this is just pulling in some details from the posts on the website (the client name and the sector).

Next, I've got "Other Clients" - this is set up as an Advanced Custom Field on the page that this code appears on. Pretty simple as well.

Now, here's the fun:

It works if I reverse the two sections ("Other Clients" first) but not this way - any ideas what's going wrong? I'm presuming it's something in the "Case Studies" section that's messing up the following one, but I'm at a loss. If I can provide any more info, let me know!

Much thanks in advance x

Answer 1

After finishing your custom query you must call wp_reset_postdata();

$the_query = new WP_Query(array(
    'post_type'         => 'post',  
    'posts_per_page'    => -1,
    'cat'               => 3,
    'meta_key'          => 'sector',
    'orderby'           => 'meta_value', 
    'order'             => 'ASC'
));

if( $the_query->have_posts() ):
while( $the_query->have_posts() ) : $the_query->the_post(); ?>

<a href="<?php echo get_permalink(); ?>">
    <h1><?php the_field('client_name'); ?></h1><p><?php the_field('sector'); ?></p>
    <span style="background-image:url(<?php $url = wp_get_attachment_url( get_post_thumbnail_id($post->ID) ); echo $url; ?>)"></span>
</a>

<?php endwhile; endif; ?>
<?php wp_reset_postdata(); ?>

Because your custom query $the_query->the_post(); overrides global $post object, after finishing your query must always do this.