题解 | #在last_update后面新增加一列名字为create_date#
构造一个触发器audit_log
http://www.nowcoder.com/practice/7e920bb2e1e74c4e83750f5c16033e2e
create trigger audit_log before insert on employees_test
for each row
begin
insert into audit (emp_no,name) values(new.id,new.name);
end;
创建触发器语法：
create trigger "trigger_name" event on table_name
for each row
begin
trigger_action
end;
其中event包含:insert、update、delete
