MySQL - auto decrementing value

Question

Let\'s say that I\'ve got a table, like that (id is auto-increment):

id | col1 | col2
1  | \'msg\'| \'msg\'
2  | \'lol\'| \'lol2\'
3  | \'xxx\'| \'x\'
         


        

Answer 1

You can renumber the whole table like this:

SET @r := 0;
UPDATE  mytable
SET     id = (@r := @r + 1)
ORDER BY
        id;