Managing a checklist We want to track progress of some projects, and I thought I'd make a mysql table of the checklist items that we'll be tracking completion dates and correlated data for.  This would be an ordered list, but being likely to be updated periodically, inserting a value in the middle is likely, and would be a nuisance.  I was wondering if there's a way of doing an insert along the lines of alter table, i.e. "insert into table set blah=blah after id=4", where id is an auto_increment and everthing 4+ would get renumbered.  Perhaps something like this post on renumbering: https://stackoverflow.com/questions/2643371/how-to-renumber-primary-index

I guess you could do this variation on that post:

SET @i=5
UPDATE table_name SET id=(@i:=@i+1) where id &gt;= 4;
INSERT into table_name SET id=4, blah='blah'


That doesn't seem too complicated, though doing it this way you probably wouldn't want it to be auto_increment (or at least it doesn't buy you much beyond the initial setup).  I'm open to a better idea though...
Don't try that approach.  Instead, create another column for the 'sequence number' of the actions.  Or simply use a DATETIME for ordering.  (Note, that has a resolution of 1 second; can two things happen in a single second?  If so, there are workarounds.)