在mysql触发器中使用case/if/else时出现语法错误

我在MySQL触发器中使用case语句。 但是在MySQL的触发器中使用case-block/if/else时出现语法错误

使用案例

DELIMITER //
CREATE DEFINER=`root`@`localhost` 
       TRIGGER `color_changed` 
       AFTER INSERT ON `tb_tickets`
       FOR EACH ROW 
BEGIN
 CASE NEW.program_id
 WHEN 1 THEN
   UPDATE tb_sites_1 
   SET color_status = NEW.status 
   WHERE site_id = NEW.site_id;
 WHEN 2 THEN
   UPDATE tb_sites_2 
   SET color_status = NEW.status 
   WHERE site_id = NEW.site_id;
 WHEN 3 THEN
   UPDATE tb_sites_3
   SET color_status = NEW.status 
   WHERE site_id = NEW.site_id;
 END
END
DELIMITER ;

CREATE DEFINER=`root`@`localhost` 
       TRIGGER `color_changed` 
       AFTER INSERT ON `tb_tickets`
       FOR EACH ROW 
BEGIN
 IF NEW.program_id = 1 THEN
   UPDATE tb_sites_1 
   SET color_status = NEW.status 
   WHERE site_id = NEW.site_id;
 ELSEIF NEW.program_id = 2 THEN
   UPDATE tb_sites_2 
   SET color_status = NEW.status 
   WHERE site_id = NEW.site_id;
 ELSE
  UPDATE tb_sites_3
   SET color_status = NEW.status 
   WHERE site_id = NEW.site_id;
 END
END;

错误 抱歉，发生了意外错误

使用IF/ELSE

DELIMITER //
CREATE DEFINER=`root`@`localhost` 
       TRIGGER `color_changed` 
       AFTER INSERT ON `tb_tickets`
       FOR EACH ROW 
BEGIN
 CASE NEW.program_id
 WHEN 1 THEN
   UPDATE tb_sites_1 
   SET color_status = NEW.status 
   WHERE site_id = NEW.site_id;
 WHEN 2 THEN
   UPDATE tb_sites_2 
   SET color_status = NEW.status 
   WHERE site_id = NEW.site_id;
 WHEN 3 THEN
   UPDATE tb_sites_3
   SET color_status = NEW.status 
   WHERE site_id = NEW.site_id;
 END
END
DELIMITER ;

CREATE DEFINER=`root`@`localhost` 
       TRIGGER `color_changed` 
       AFTER INSERT ON `tb_tickets`
       FOR EACH ROW 
BEGIN
 IF NEW.program_id = 1 THEN
   UPDATE tb_sites_1 
   SET color_status = NEW.status 
   WHERE site_id = NEW.site_id;
 ELSEIF NEW.program_id = 2 THEN
   UPDATE tb_sites_2 
   SET color_status = NEW.status 
   WHERE site_id = NEW.site_id;
 ELSE
  UPDATE tb_sites_3
   SET color_status = NEW.status 
   WHERE site_id = NEW.site_id;
 END
END;

错误

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#1064-您的SQL语法有错误；查看与您的MySQL服务器版本对应的手册，以了解第9行的“”附近使用的正确语法。阅读整个注释时，最好始终使用该语法。你错过了最后的机会；和结束//（用于开始）

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如果您有任何其他错误，请添加完整错误。

语法错误的具体状态是什么？#1064.您的SQL语法有错误；检查与您的MySQL服务器版本相对应的手册，以了解在第10行@EricJ的“”附近使用的正确语法。是否设置分隔符？case语句需要以end case结尾；以及如果声明需要终止，且终止条件为：；与开始匹配的结尾应该以您设置的分隔符终止。请阅读此内容，我面临另一个触发错误，您能帮忙吗