触发器内select语句中的MySQL错误

我最近开始研究MySQL n，现在我想创建一个触发器，但是MySQL在语法上返回了一个错误

delimiter $$;
create trigger abc after insert on ratings
for each row
    begin
        set @n1 = select avg(rating) from ratings join users where ratings.uname=users.uname 
        and ratings.bookid=new.bookid users.`type`='admin' or users.`type`='critic';
        update books set avgcriticrating = @n1 where bookid=new.bookid;
end;

select语句在单独触发时运行良好，但在触发器内部使用时出现错误

下面是MySQL给出的错误

#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'select avg(rating) from ratings join users where ratings.uname=users.uname an' at line 4

books和ratings表都包含一个名为bookid的字段

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请帮助

如果希望从select语句中获得单个值，则该语句必须位于（括号）中

下一个错误将发生在

new.bookid用户处

-可能有

和
或
缺失

set @n1 = (select avg(rating) from ratings join users where ratings.uname=users.uname 
    and ratings.bookid=new.bookid users.`type`='admin' or users.`type`='critic');