filling a table by triggering multiple tables on insert I have a table m contains the following fields:

id int(11) not null auto_increment, //PK
name varchar(100) null,
something_else varchar(100) default 'not important'


I need to fill up table m by using this trigger

CREATE TRIGGER some_name AFTER INSERT ON `x` FOR EACH ROW INSERT INTO m (name) VALUES (NEW.name);


which I got from this dba question

but the problem is that each row on m should be filled using after insert on multiple different tables like x,y. So, how can this be done.

I hope that my question is clear enough as it is in my mind.

Update 1:
table m has the following row:

id - name - something_else
1  - null - not important


on after insert for table x, table m row should become like:

id - name     - something_else
1  - newthing - not important


then, on after insert for table y, table m row should become like:

id - name     - something_else
1  - newthing - new value


Hence, the row on table m had been filled by multiple inserts on different tables and updated accordingly.
The trigger code you just displayed in your question needs to be manually defined on each table you intend to copy from. For tables x, y and z the answer to your question is:
CREATE TRIGGER some_name AFTER INSERT ON `x` FOR EACH ROW INSERT INTO m (name) VALUES (NEW.name);
CREATE TRIGGER some_name AFTER INSERT ON `y` FOR EACH ROW INSERT INTO m (name) VALUES (NEW.name);
CREATE TRIGGER some_name AFTER INSERT ON `z` FOR EACH ROW INSERT INTO m (name) VALUES (NEW.name);

I suggest you make table m use MyISAM to prevent all potential deadlocks.
UPDATE 2013-10-15 19:39 EDT
First, define the table m  like this:
CREATE TABLE m
(
    id int(11) not null auto_increment, //PK
    name varchar(100) null,
    something_else varchar(100) default 'not important',
    primary key (id),
    unique key (name)
) ENGINE = MyISAM;

Then, make the trigger like this:
CREATE TRIGGER some_name AFTER INSERT ON `x`
FOR EACH ROW
    INSERT INTO m (name) VALUES (NEW.name)
    ON DUPLICATE KEY UPDATE
    SET something_else = 'new thing'
;

I would suggest that make something_else have the date and time as well
CREATE TRIGGER some_name AFTER INSERT ON `x`
FOR EACH ROW
    INSERT INTO m (name) VALUES (NEW.name)
    ON DUPLICATE KEY UPDATE
    SET something_else = CONCAT('new thing ',NOW());
;

and maybe the table where the insert came from
CREATE TRIGGER some_name AFTER INSERT ON `x`
FOR EACH ROW
    INSERT INTO m (name) VALUES (NEW.name)
    ON DUPLICATE KEY UPDATE
    SET something_else = CONCAT('new thing from x : ',NOW());
;

Give it a Try !!!