I was using the following arguments for a WP_Query for months:

$args = array(
    'post_type' => array( 'posttype1', 'posttype2', 'posttype3', 'posttype4' ),
    'posts_per_page' => -1,
    'meta_query' => array(
        'relation' => 'OR',
        array('key' => 'field1_0_subfield'),
        array('key' => 'field2'),
        array('key' => 'field3_0_subfield'),
        array('key' => 'field4' )
    'meta_key' => 'meta_value',
    'orderby' => 'meta_value',
    'order' => 'ASC'

There are four different post types querried (posttype1, posttype2, posttype3, posttype4). The meta_query querries ACF (Advanced Custom Fields) fields (field2, field4) as well as ACF subfields (field1_0_subfield, field3_0_subfield) containing dates each. So the entries in the four post types are sorted by date ascending chronologically. With the update to Wordpress 4.1 the query stopped working and i have no idea about the reason.

  • Yep i am aware that the wp_meta_query has changed quite a bit, basically it is more ore less a complete rewrite of the function. But in my present example nesting wouldn't make sense like shown in the nested meta query examples - i just have 4 single fields/keys with an OR relation. Basically it should just go on working since the syntax hasn't changed as well imho :/
    – rkoller
    Dec 20, 2014 at 15:07

1 Answer 1


The problem is with the arg 'meta_key' => 'meta_value' - meta_key isn't needed if you have a meta_query arg (despite what the codex appears to say) and its value here doesn't make sense anyway - so just remove it.

However it does point out a behavioural change in 4.1 as before the meta_key was ORed with the meta_query keys (hence your query worked as the meta_key = 'meta_value' clause was basically a no-op) but now it's ANDed and so fails. WP 4.0.1:

wp_postmeta.meta_key = 'meta_value' OR wp_postmeta.meta_key = 'field1_0_subfield' OR wp_postmeta.meta_key = 'field2' ...

WP 4.1 (mt1 being an alias of wp_postmeta):

wp_postmeta.meta_key = 'meta_value' AND (mt1.meta_key = 'field1_0_subfield' OR mt1.meta_key = 'field2' ...)

(PS an easy way to see what SQL is being produced by a query is to look at $query->request.)

  • Thanks a lot for the clarification - explained things perfectly! I think the old Codex page i've got the info from was a bit misleading. Works now. Thanks again!
    – rkoller
    Dec 21, 2014 at 3:46

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