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

```

`103` is missing. How I can update all the rows so that the order becomes correct (`104` becomes `103` in my example) in one SQL command?

Answer: 
Try this:

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

```
Another way, without truncating whole table:

```
-- Make Backup of original table's content
CREATE TABLE `orig_tbl_backup` SELECT * FROM `orig_tbl`;
-- Drop needed column. 
ALTER TABLE `orig_tbl` DROP `id`;
-- Re-create it
ALTER TABLE `orig_tbl` AUTO_INCREMENT = 1;
ALTER TABLE `orig_tbl` ADD `id` int UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY FIRST;

```