题解 | #将employees表中的所有员工的last_name和first_name通过引号连接起来。#

select concat(last_name,"'",first_name) name from employees
* 一次性的更改
alter table employees drop column name;
alter table employees add column name varchar(45);
update employees set name=concat(last_name,"'",first_name)

* 使用触发器在插入和更新数据的时候更新name
drop trigger if exists i_name;
create trigger i_name before insert on employees
for each ROW
set new.name=concat(new.last_name,"'",new.first_name);

drop trigger if exists u_name;
create trigger u_name before update on employees
for each ROW
set new.name=concat(new.last_name,"'",new.first_name);