$sql = "
CREATE TRIGGER `_photo_fulltext_insert` AFTER INSERT ON `photo` FOR each ROW INSERT INTO `_photo_fulltext` SELECT * From `photo` WHERE `id`=NEW.`id`;
CREATE TRIGGER `_photo_fulltext_delete` AFTER DELETE ON `photo` FOR EACH ROW DELETE From `_photo_fulltext` WHERE `id`=OLD.`id`;

DELIMITER |
CREATE TRIGGER `_photo_fulltext_update` AFTER UPDATE ON `photo`
  FOR EACH ROW BEgin
    DELETE FROM `_photo_fulltext` WHERE `id`=NEW.`id`;
    INSERT INTO `_photo_fulltext` SELECT * FROM `photo` WHERE `id`=NEW.`id`;
  END;
|
DELIMITER ;
";

$MysqLi->;multi_query($sql);

虽然MysqLi在多查询语句中没有任何与DELIMITER相关的东西,但它在普通查询中根本不对任何分隔符做任何事情,所以只需逐个推送你的触发器：

$cat i.PHP 
<?PHP
$MysqLi = new MysqLi('localhost','test','','test');
$sql = "
CREATE TRIGGER `_foo_fulltext_update` AFTER UPDATE ON `foo`
  FOR EACH ROW BEGIN
    DELETE FROM `bar` WHERE `bar`=NEW.`bar`;
    INSERT INTO `bar` (bar) SELECT bar FROM `foo` WHERE `bar`=NEW.`bar`;
  END;
";
$MysqLi->query($sql);
var_dump($MysqLi->error);
$PHP i.PHP 
string(0) ""
$MysqL
MysqL> use test;

Database changed
MysqL> show triggers\G
*************************** 1. row ***************************
             Trigger: _foo_fulltext_update
               Event: UPDATE
               Table: foo
           statement: BEGIN
    DELETE FROM `bar` WHERE `bar`=NEW.`bar`;
    INSERT INTO `bar` (bar) SELECT bar FROM `foo` WHERE `bar`=NEW.`bar`;
  END
              Timing: AFTER
             Created: NULL
            sql_mode: 
             definer: root@localhost
character_set_client: latin1
collation_connection: latin1_swedish_ci
  Database Collation: utf8_general_ci
1 row in set (0.00 sec)