<p>I would like to create a stored procedure in MySQL that took a list as argument. For example, say that I would like to be able to set multiple tags for an item in one call, then what I want to do is to define a procedure that takes the ID of the item and a list of tags to set. However, I can't seem to find any way to do this, there is no list datatype, as far as I'm aware, but can it be emulated somehow? Could the list of tags be a comma-separated string, which can somehow be split and looped over?</p>

<p>How do you usually work with lists in MySQL stored procedures?</p>

Not sure if these will work specifically in a SP, but there are ENUM and SET datatypes in MySQL 5 which may do what you need.
http://dev.mysql.com/doc/refman/5.0/en/enum.html
http://dev.mysql.com/doc/refman/5.0/en/set.html