+/**
+ * Given a meta query, generates SQL clauses to be appended to a main query
+ *
+ * @since 3.1.0
+ * @access private
+ *
+ * @param array $meta_query List of metadata queries. A single query is an associative array:
+ * - 'key' string The meta key
+ * - 'value' string|array The meta value
+ * - 'compare' (optional) string How to compare the key to the value.
+ * Possible values: '=', '!=', '>', '>=', '<', '<=', 'LIKE', 'NOT LIKE', 'IN', 'NOT IN', 'BETWEEN', 'NOT BETWEEN'.
+ * Default: '='
+ * - 'type' string (optional) The type of the value.
+ * Possible values: 'NUMERIC', 'BINARY', 'CHAR', 'DATE', 'DATETIME', 'DECIMAL', 'SIGNED', 'TIME', 'UNSIGNED'.
+ * Default: 'CHAR'
+ *
+ * @param string $meta_type
+ * @param string $primary_table
+ * @param string $primary_id_column
+ * @param object $context (optional) The main query object
+ * @return array( 'join' => $join_sql, 'where' => $where_sql )
+ */
+function _get_meta_sql( $meta_query, $meta_type, $primary_table, $primary_id_column, $context = null ) {
+ global $wpdb;
+
+ if ( ! $meta_table = _get_meta_table( $meta_type ) )
+ return false;
+
+ $meta_id_column = esc_sql( $meta_type . '_id' );
+
+ $join = '';
+ $where = '';
+ $i = 0;
+ foreach ( $meta_query as $q ) {
+ $meta_key = isset( $q['key'] ) ? trim( $q['key'] ) : '';
+ $meta_value = isset( $q['value'] ) ? $q['value'] : '';
+ $meta_compare = isset( $q['compare'] ) ? strtoupper( $q['compare'] ) : '=';
+ $meta_type = isset( $q['type'] ) ? strtoupper( $q['type'] ) : 'CHAR';
+
+ if ( ! in_array( $meta_compare, array( '=', '!=', '>', '>=', '<', '<=', 'LIKE', 'NOT LIKE', 'IN', 'NOT IN', 'BETWEEN', 'NOT BETWEEN' ) ) )
+ $meta_compare = '=';
+
+ if ( 'NUMERIC' == $meta_type )
+ $meta_type = 'SIGNED';
+ elseif ( ! in_array( $meta_type, array( 'BINARY', 'CHAR', 'DATE', 'DATETIME', 'DECIMAL', 'SIGNED', 'TIME', 'UNSIGNED' ) ) )
+ $meta_type = 'CHAR';
+
+ if ( empty( $meta_key ) && empty( $meta_value ) )
+ continue;
+
+ $alias = $i ? 'mt' . $i : $meta_table;
+
+ $join .= "\nINNER JOIN $meta_table";
+ $join .= $i ? " AS $alias" : '';
+ $join .= " ON ($primary_table.$primary_id_column = $alias.$meta_id_column)";
+
+ $i++;
+
+ if ( !empty( $meta_key ) )
+ $where .= $wpdb->prepare( " AND $alias.meta_key = %s", $meta_key );
+
+ if ( in_array( $meta_compare, array( 'IN', 'NOT IN', 'BETWEEN', 'NOT BETWEEN' ) ) ) {
+ if ( ! is_array( $meta_value ) )
+ $meta_value = preg_split( '/[,\s]+/', $meta_value );
+ } else {
+ $meta_value = trim( $meta_value );
+ }
+
+ if ( empty( $meta_value ) )
+ continue;
+
+ if ( 'IN' == substr( $meta_compare, -2) ) {
+ $meta_compare_string = '(' . substr( str_repeat( ',%s', count( $meta_value ) ), 1 ) . ')';
+ } elseif ( 'BETWEEN' == substr( $meta_compare, -7) ) {
+ $meta_value = array_slice( $meta_value, 0, 2 );
+ $meta_compare_string = '%s AND %s';
+ } elseif ( 'LIKE' == substr( $meta_compare, -4 ) ) {
+ $meta_value = '%' . like_escape( $meta_value ) . '%';
+ $meta_compare_string = '%s';
+ } else {
+ $meta_compare_string = '%s';
+ }
+
+ // @todo Temporary hack to support empty values. Do not use outside of core.
+ if ( '_wp_zero_value' == $meta_value )
+ $meta_value = 0;
+
+ $where .= $wpdb->prepare( " AND CAST($alias.meta_value AS {$meta_type}) {$meta_compare} {$meta_compare_string}", $meta_value );
+ }
+
+ return apply_filters_ref_array( 'get_meta_sql', array( compact( 'join', 'where' ), $meta_query, $meta_type, $primary_table, $primary_id_column, &$context ) );
+}
+
+/**
+ * Populates the $meta_query property
+ *
+ * @access private
+ * @since 3.1.0
+ *
+ * @param array $qv The query variables
+ */
+function _parse_meta_query( &$qv ) {
+ $meta_query = array();
+
+ // Simple query needs to be first for orderby=meta_value to work correctly
+ foreach ( array( 'key', 'value', 'compare', 'type' ) as $key ) {
+ if ( !empty( $qv[ "meta_$key" ] ) )
+ $meta_query[0][ $key ] = $qv[ "meta_$key" ];
+ }
+
+ if ( !empty( $qv['meta_query'] ) && is_array( $qv['meta_query'] ) ) {
+ $meta_query = array_merge( $meta_query, $qv['meta_query'] );
+ }
+
+ $qv['meta_query'] = $meta_query;
+}
+