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

[nacin]

Try meta_value_num

[hetjens]

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

[mdawaffe]

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

We could probably use strlen(), though.

[dd32]

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.

[dd32]

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 != )

[scribu]

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

Also see unit-meta-query.php​.

[scribu]

Don't use array_filter()

[scribu]

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

[scribu]

Related: #17011

[ryan]

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

[scribu]

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​

[ryan]

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