$r1 = q("ALTER TABLE `sign` ALTER `iid` SET DEFAULT '0'");
$r2 = q("ALTER TABLE `sign` ADD `retract_iid` INT(10) UNSIGNED NOT NULL DEFAULT '0' AFTER `iid`");
$r3 = q("ALTER TABLE `sign` ADD INDEX ( `retract_iid` )");
$r1 = q("ALTER TABLE `sign` ALTER `iid` SET DEFAULT '0'");
$r2 = q("ALTER TABLE `sign` ADD `retract_iid` INT(10) UNSIGNED NOT NULL DEFAULT '0' AFTER `iid`");
$r3 = q("ALTER TABLE `sign` ADD INDEX ( `retract_iid` )");