sql - How to renumber primary index

Question

I have got a simple MySQL table and primary index (id) is not numbered one by one (1, 31, 35, 100 etc.). I want them to be numbered like (1, 2, 3, 4). Please tell me how to do it. I would also like to point that I am aware of possible consequences of the operation, but I just want to tidy up the table.

Answer 1

I agree other methods will work but I'm just giving a different idea. This will do without any temp table creation requirements::

SET @i=0;
UPDATE table_name SET column_name=(@i:=@i+1);