[wp-trac] [WordPress Trac] #24093: WP_Meta_Query is inefficient when referencing the same keys in "OR" query

[WordPress Trac]

#24093: WP_Meta_Query is inefficient when referencing the same keys in "OR" query
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 Reporter:  sc0ttkclark                          |       Owner:
     Type:  enhancement                          |      Status:  new
 Priority:  normal                               |   Milestone:  Awaiting
Component:  Query                                |  Review
 Severity:  normal                               |     Version:  3.5.1
 Keywords:  has-patch needs-testing dev-         |  Resolution:
  feedback                                       |
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Comment (by F J Kaiser):

 Stumbled upon this patch/ticket while updating Codex on
 [http://codex.wordpress.org/Class_Reference/WP_Meta_Query WP_Meta_Query].
 Nice patch! Finally.

 Just one note: If you use a {{{meta_query}}} array

 {{{
 $query_args = array( 'meta_query' => array(
         'relation' => 'OR',
         array(
                 'key' => 'foo_key',
                 // 'value' => 'foo',
                 // 'compare' => 'LIKE',
         ),
         array(
                 'key' => 'bar_key',
         ),
 ) );
 $meta_query = new WP_Meta_Query();
 $meta_query->parse_query_vars( $query_args );
 $mq_sql = $meta_query->get_sql(
         'post',
         $wpdb->posts,
         'ID',
         null
 );
 }}}

 that only searches for two key/value pairs (so two subarrays), then it
 will '''still''' do a join on the native table names like

 {{{
 INNER JOIN wp_postmeta ON wp_post.ID = wp_postmeta.post_id
 }}}

 and then do an additional

 {{{
 INNER JOIN wp_postmeta AS mt{$i} ON (wp_posts.ID = {$alias}{$i}.post_id)
 }}}

 so the result will look like:

 {{{
 'join' => string ' INNER JOIN wp_postmeta ON wp_posts.ID =
 wp_postmeta.post_id INNER JOIN wp_postmeta AS mt1 ON (wp_posts.ID =
 mt1.post_id)'
 }}}

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Ticket URL: <http://core.trac.wordpress.org/ticket/24093#comment:2>
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