It's not possible to check for "meta_value = 0" in wp_query->get_posts

[hetjens]

Because of the "empty" function of php it isn't possible to check for a meta_value = 0 in wp_query->get_posts.

My Case:

'meta_key' => '_menu_item_menu_item_parent',
'meta_value' => '0',

wp-includes/query.php Line 2307 is:
if ( ! empty($q['meta_value']) ) {

But empty() says that String "0" is true

So the query will return all posts that have a meta-field "_menu_item_menu_item_parent" and not only the posts with "_menu_item_menu_item_parent = 0" (which means, that it's an menu root item)

My solution is:

if (( ! empty($q['meta_value']) ) || ($q['meta_value'] == '0')) {

but that's not very nice. Any better idea?

Thanks,
Philip

Try meta_value_num

meta_value_num is only for orderby and not for checking against it.

In 3.1, you can pass meta_value = '_wp_zero_value'.

We could probably use strlen(), though.

Closed Ticket #16573 as duplicate.

In 3.1, you can pass meta_value = '_wp_zero_value'.

For any developers coming across this, Please do not use it. Yes, It works in 3.1 but it's an internal hack only.. You cannot rely on this being there for 3.2.

using strlen() on Line 423 will probably fix this ticket.

using strlen() on Line 423 will probably fix this ticket.

but would have the effect that you can't query against a literal, empty string.

Closed #16735 as duplicate (cannot query meta_Value != )

16573.diff​ should cover this ticket as well as #16735.

Also see unit-meta-query.php​.

Don't use array_filter()

This ​answer made me realize that I shouldn't be using array_filter(). Hence, 16573.2.diff​. Also updated the unit tests.

Related: #17011

Let's remove the zero value hacks introduced in [17088] and make sure wp_dropdown_users() works with this new patch.

Replying to ryan:

Let's remove the zero value hacks introduced in [17088] and make sure wp_dropdown_users() works with this new patch.

Done: 16573.3.diff​

(In [17674]) Allow querying empty meta values. Props scribu. fixes #15292