How can I tidy up an auto increment field in a table from within a module? How can I tidy up an auto increment field in a table from within a module, so that a table like this (the 'id' field being auto incrementing):

id title
1  foo
3  bar
7  fee


becomes:

id title
1  foo
2  bar
3  fee


Is there a function, like serial_field_tidy or something?
You should never do that since the IDs are important for addressing to that specific row in other tables. You would never know which modules are also indexed this row with its id. So if you change the ID of a row, you will encounter unexpected things in your installation.