Auto update DATETIME column on insert with SQL?

Question

I am currently just inserting NOW() into the date field on my database which works just fine but it got me wondering, is there a way to automatically update a DATETIME row upon inserting data?

I found online in some places that I should set the extras to ON UPDATE CURRENT_TIMESTAMP but when doing this I get the following error:

An error occurred when trying to change the field 'uploaded' via

ALTER TABLE `uploads` CHANGE `uploaded` `uploaded` DATETIME
 NOT NULL
 ON UPDATE CURRENT_TIMESTAMP
 COMMENT 'Upload Datetime'

MySQL said:

Invalid ON UPDATE clause for 'uploaded' column

Answer 1

This is what I do and it has always worked

create table if not exists my_table (
    index1 char(32) not null primary key,
    title varchar(50),
    my_timestamp timestamp not null default current_timestamp on update current_timestamp
)

This will have the timestamp on inserts and on updates, it also is valid sql, maybe you are missing the default statement in your query?