postgresqlnow()返回类型

CREATE OR REPLACE FUNCTION score_audit() 
RETURNS TRIGGER AS 
$score_audit$
 BEGIN 
    IF(TG_OP = 'DELETE') THEN
        INSERT INTO audit_score ("USERNAME","SID","CID",updatetime,oldscore) SELECT
user,old."SID",old."CID", now() ,old."Score";
        RETURN OLD;
    ELSIF (TG_OP = 'UPDATE') THEN
        INSERT INTO audit_score ("USERNAME","SID","CID",updatetime,oldscore,newscore) SELECT
USER,old."SID",old."CID",current_timestamp,old."Score",new."Score"
        where old."SID"=NEW."SID" AND OLD."CID"=NEW."CID";
        RETURN NEW;
    ELSIF (TG_OP = 'INSERT') THEN
        INSERT INTO audit_score ("USERNAME","SID","CID",updatetime,oldscore,newscore) SELECT
USER,old."SID",old."CID",now(),NULL,new."Score";
        RETURN NEW;
    END IF;
    RETURN NULL;
 END;
$score_audit$ LANGUAGE plpgsql;
        

这是各grade表上的触发器
update修改表grade后显示

ERROR: 错误:  关系 "audit_score" 的 "updatetime" 字段不存在
LINE 1: INSERT INTO audit_score ("USERNAME","SID","CID",updatetime,o...
                                                        ^
QUERY:  INSERT INTO audit_score ("USERNAME","SID","CID",updatetime,oldscore,newscore) SELECT
USER,old."SID",old."CID",current_timestamp,old."Score",new."Score"
        where old."SID"=NEW."SID" AND OLD."CID"=NEW."CID"
CONTEXT:  在SQL语句的第8行的PL/pgSQL函数score_audit()

表audit_score没有字段updatetime