Incremental create trigger addition, deletion, and modification

Demo

Add
Drop trigger if exists t_tab;
Create trigger t_tab
After insert on friend
For each row
Begin
Insert into friend_1 (ID, mqq, fqq, update1) values (New. ID, new. mqq, new. fqq, "add ");
End;

Insert into friend (mqq, fqq) values (1, 2 );

Modify
Drop trigger if exists t_tab_update;
Create trigger t_tab_update
After update on friend
For each row
Begin
Update friend_1 set mqq = new. mqq, fqq = new. fqq, update1 = "up" where id = new. ID;
End;

Update friend set mqq = 4 where id = 79;

Delete
Drop trigger if exists t_tab_delete;
Create trigger t_tab_delete
Before delete on friend
For each row
Begin
Update friend_1 set update1 = "delete" where id = old. ID;
End;

Delete from friend where id = 79;