Question

This is schoolwork..
I’m trying to create a table that has a default date value in the future and found a great solution here. This answer says that if a date is given in the INSERT statement, it will override the trigger. However, when I try to populate the table with some old data including a date, the trigger clobbers the date. I feel I’m just missing something obvious.

create table member (
    member_id int not null primary key auto_increment,
    last_name varchar(25) not null,
    first_name varchar(25),
    address varchar(100),
    city varchar(30),
    phone varchar(15),
    join_date datetime not null);
create trigger setJoinDate
    before insert on member
    for each row
    set NEW.join_date = curdate();

So when I insert some data:

insert into member
    set
        first_name = 'Midori',
        last_name = 'Nagayama',
        address = '68 Via Centrale',
        city = 'Sao Paolo',
        phone = '254-852-5764',
        join_date = '1991-6-17';

The date gets overridden:

mysql> select first_name,join_date from member;
+------------+---------------------+
| first_name | join_date           |
+------------+---------------------+
| Midori     | 2012-03-18 00:00:00 |
+------------+---------------------+

Answer 1

You need to add a conditional to the trigger.

For example:

create trigger setJoinDate
    before insert on member
    for each row
    set NEW.join_date = IFNULL(NEW.join_date, CURDATE());