How to reorder a primary key?

Question

I have a table of 5700 records. The primary key is an integer. Now I noticed that some values are missing. Like this:

100 data
101 data 
102 data
104 data
         


        

Answer 1

Try this:

SET @var:=0;
UPDATE `table` SET `id`=(@var:=@var+1);
ALTER TABLE `table` AUTO_INCREMENT=1;