Problem with auto-incremented “id” column

Question

My db table looks like this pic. http://prntscr.com/22z1n

Recently I\'ve created delete.php page. it works properly but when i deleted 21th user next registered use

Answer 1

Easily, no. What you can do (but I don't suggest doing) is making an SQL function to determine the lowest number that isn't currently occupied. Or you can create a table of IDs that were deleted, and get the smallest number from there. Or, and this is the best idea, ignore the gaps and realize the database is fine.