Question

How to sort Username correctly?

For example I do this query:

SELECT * FROM  `members` WHERE username LIKE  'bx%' ORDER BY username ASC 

Result:

bx1
bx10
bx11
bx12
bx13
bx14
bx15
bx16
bx17
bx18
bx19
bx2
bx20
bx21
bx3
bx4
bx5

I want to return like this:

bx1
bx2
bx3
bx4
bx5
...
bx15
bx16

and so on

Answer 1

SELECT *
FROM `members`
WHERE username LIKE 'bx%'
ORDER BY LENGTH(username), username

The fact that you need to do this tells me your schema is denormalized. If possible, store the integer part of the username in a separate column if you need to do operations on it.

SQL Fiddle Example