Get post_id from meta_key => meta_value

vc_get_post_id_by_meta__key_value

/**
 * Get post_id from meta_key => meta_value
 *
 * @version 0.1
 * @updated 07.30.12
 *
 **/
function vc_get_post_id_by_meta__key_value( $meta_key, $meta_value, $limit = 1 ) {
	global $wpdb;
	
	$querystr = "SELECT $wpdb->postmeta.post_id FROM $wpdb->postmeta WHERE $wpdb->postmeta.meta_key = '$meta_key' AND $wpdb->postmeta.meta_value = '$meta_value' LIMIT $limit";
	$results = $wpdb->get_results( $querystr );
	if ( isset( $results[0]->post_id ) AND is_numeric( $results[0]->post_id ) )
		return $results[0]->post_id;
	else
		return false;
	
} // end function vc_get_post_id_by_meta__key_value