如何编写一个MySQL触发器以将行插入到另一个表中？?mysql

drop table if exists comments; create table comments ( comment_id int unsigned not null auto_increment primary key, user_id int unsigned not null ) engine=innodb;

drop table if exists activities; create table activities ( activity_id int unsigned not null auto_increment primary key, comment_id int unsigned not null, user_id int unsigned not null ) engine=innodb;

delimiter #

create trigger comments_after_ins_trig after insert on comments for each row begin insert into activities (comment_id, user_id) values (new.comment_id, new.user_id); end#

delimiter ;

insert into comments (user_id) values (1),(2);

select * from comments; select * from activities; 编辑：

mysql> . d:\foo.sql

Database changed Query OK, 0 rows affected (0.10 sec)

Query OK, 0 rows affected (0.30 sec)

Query OK, 0 rows affected (0.11 sec)

Query OK, 0 rows affected (0.35 sec)

Query OK, 0 rows affected (0.07 sec)

Query OK, 2 rows affected (0.03 sec) Records: 2 Duplicates: 0 Warnings: 0

+------------+---------+ | comment_id | user_id | +------------+---------+ | 1 | 1 | | 2 | 2 | +------------+---------+ 2 rows in set (0.00 sec)

+-------------+------------+---------+ | activity_id | comment_id | user_id | +-------------+------------+---------+ | 1 | 1 | 1 | | 2 | 2 | 2 | +-------------+------------+---------+ 2 rows in set (0.00 sec)来源：stack overflow