Ticket #22967: 22967.2.patch

src/wp-includes/meta.php

@@ -753 +753 @@
                 // Split out the meta_key only queries (we can only do this for OR)
                 if ( 'OR' == $this->relation ) {
                         foreach ( $this->queries as $k => $q ) {
-                                if ( ! isset( $q['value'] ) && ! empty( $q['key'] ) )
+                                if ( ! array_key_exists( 'value', $q ) && ! empty( $q['key'] ) )
                                         $key_only_queries[$k] = $q;
                                 else
                                         $queries[$k] = $q;
@@ -774 +774 @@
                         $meta_key = isset( $q['key'] ) ? trim( $q['key'] ) : '';
                         $meta_type = $this->get_cast_for_type( isset( $q['type'] ) ? $q['type'] : '' );
 
+                        if ( array_key_exists( 'value', $q ) && is_null( $q['value'] ) )
+                                $q['value'] = '';
+
                         $meta_value = isset( $q['value'] ) ? $q['value'] : null;
 
                         if ( isset( $q['compare'] ) )

tests/phpunit/tests/meta/query.php

@@ -105 +105 @@
                 $this->assertEquals( 1, substr_count( $sql['where'], "$wpdb->postmeta.meta_key = 'my_third_key'" ) );
 
         }
+
+        /**
+         * @ticket 22967
+         */ 
+        function test_null_value_sql() {
+                global $wpdb;
+
+                $query = new WP_Meta_Query( array(
+                        array( 'key' => 'abc', 'value' => null, 'compare' => '=' )
+                ) );
+                $sql = $query->get_sql( 'post', $wpdb->posts, 'ID', $this );
+
+                $this->assertEquals( 1, substr_count( $sql['where'], "CAST($wpdb->postmeta.meta_value AS CHAR) = '')" ) );
+        }
 }