wordpress WP Query and Custom Field filtering - filtering

Question

I've encoutered problem with filtering pages to display in WP query.
I use Codex WP query reference for custom fields with ACF (Advanced Custom Fields plugin - but it doesn't matter, couse it works same as WP custom field) parameters to filter pages.
In "Multiple Custom Field Handling" paragraph, Codex got an example with 2 conditions. We can use OR or AND relation. I works for both until you have 3rd condition (array).
They use example:
'relation' => 'OR',
array(
'key' => 'color',
'value' => 'blue',
'compare' => 'NOT LIKE'
),
array(
'key' => 'price',
'value' => array( 20, 100 ),
'type' => 'numeric',
'compare' => 'BETWEEN'
)
It has only 2 arrays. When I put 3rd, nothing shows. In debug mode I can see an error:
WordPress database error: [Lost connection to MySQL server during query]
When I use AND it works, but I got to use OR. Unfortunately it makes MySQL disconnect.
I've tryed asking phpMySQL for same query WP does. It couses problem - phpMyAdmin says same:
Lost connection
Any Idea?
Maybe I should try different aproach for filtering? (maybe I should use taxonomy?)
Here is code I use:
$query_array = array('relation' => 'OR');
array_push($query_array,
array(
'key' => 'filter1',
'value' => 'value1',
'compare' => 'LIKE'
),
array(
'key' => 'filter1',
'value' => 'value2',
'compare' => 'LIKE'
),
array(
'key' => 'filter1',
'value' => 'value3',
'compare' => 'LIKE'
)
);
$args = array(
'order' => $order_array,
'meta_key' => $meta_key,
'orderby' => $orderby,
'post_type' => 'page',
'paged' => $paged,
'post__in' => $postIDs,
'posts_per_page' => 12,
'paged' => get_query_var('paged'),
'meta_query' => $query_array
);
query_posts($args);
?>
(variables for $args are set of course)
I don't know why I can't use
'compare' => '='
but probably it is why I can't use:
$query_array = array('relation' => 'OR');
array_push($query_array,
array(
'key' => 'filter1',
'value' => array('value1', 'value2', 'value3'),
'compare' => 'IN'
)
);

Answer 1

Just wanted to say that your comment helped me; I'd been butting my head against a very similar problem for a while. I'm using ACF too, and using it to attach items of one post type to another custom post type was easy - for instance, to Attach Person_1 and Person_3 to "Project_A".
This made it easy to list out which users were attached to specific projects. But when it came to do the same in reverse - to show which projects were attached to which users - it became a massive headache.
I finally figured it out, in part thanks to your comment - I'll post my solution here in case someone else comes along with the same problem:
$args = array(
'numberposts' => -1,
'post_type' => 'project',
'meta_query' => array(
'relation' => 'IN',
array(
'key' => 'people',
'value' => ';s:1:"' . $person->ID . '";',
'compare' => 'LIKE'
)
)
);
In short: because the ACF values in repeater fields et cetera are serialized, the compare keyword has to be "LIKE", and I added some context to the value to eliminate false returns - just searching for an ID like "1" would match a lot of the (wrong) posts, but the ";s1;" part ensures that the given value is at index 1, which in my case is the correct index.
So it would need tweaking from case to case. Inspecting what you're trying to match up with var_dumping "get_post_meta($post->ID, 'people')" is helpful for getting the value correct.