请教下触发器怎么写啊？需求是当A表中有数据插入时，根据A表中插入数据的ID字段取B表中相应的姓名字段更新A表中插入的数据

CREATE TRIGGER 触发器名 AFTER INSERT/UPDATE/DELETE ON 表名 REFERENCING
NEW AS new FOR EACH ROW MODE DB2SQL
WHEN (NEW.BIRTH IS NULL AND new.sickid IS NOT NULL) --条件
BEGIN ATOMIC
UPDATE CL_CASE SET BIRTH = (SELECT BIRTH from HC_SICKMANINFO a
WHERE a.SICKMANID=CL_CASE.SICKMANID)
WHERE CCASENO = NEW.ccaseno;
END;