自动创建字母数字列 - SQL 服务器

Question

Is there anyway to auto generate specific alpha numeric data in a primary key column? The column has maximum length of 2 characters.

The table looks like this:

id
----
4S
33
J6
US

I'm looking to create a stored procedure that inserts a random 2 alpha numeric characters value. Is this possible in SQL Server?

I need it to be auto generated with a combination like

id like '[A-Z][0-9]') 
  or (id like '[A-Z][A-Z]' )
  or (id like '[0-9][0-9]' )
  or (id like '[0-9][A-Z]' )

Answer 1

Don't do it.

Primary keys are internal row identifiers, that are not supposed to be sexy or good looking. Their purpose is to uniquely identify rows and no more.

If you need a key to have some format it means you probably want to expose it somewhere, in the user interface or through an API; primary keys are not suitable to be exposed to the world.

Now, if you need to expose a key, then you can create a secondary key. This could be an extra column, maybe an auto-generated virtual column, or maybe it can be populated using a trigger.

Answer 2

Actually you have 2 problems:

1. Unique random number

You can find answers here: Generate list of new unique random numbers in T-SQL

2. convert regular (base10) number to Base36 ('0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ')

For 2 characters length you can use this code:

DECLARE @Base10ToBase36 AS TABLE (
    ID      TINYINT NOT NULL IDENTITY(0,1) PRIMARY KEY,
    Symbol  CHAR(1) NOT NULL CHECK(Symbol LIKE '[0-9,A-Z]')
)

INSERT INTO @Base10ToBase36(Symbol)
VALUES  ('0'), ('1'), ('2'), ('3'), ('4'), ('5'), ('6'), ('7'), ('8'), ('9'), 
        ('A'), ('B'), ('C'), ('D'), ('E'), ('F'), ('G'), ('H'), ('I'), ('J'),
        ('K'), ('L'), ('M'), ('N'), ('O'), ('P'), ('Q'), ('R'), ('S'), ('T'),
        ('U'), ('V'), ('W'), ('X'), ('Y'), ('Z')

SELECT  TOP (1) 
        pos1.ID * 36 + pos0.ID AS Base10Number,
        pos1.Symbol,
        Pos0.Symbol,
        CONCAT(pos1.Symbol, Pos0.Symbol) AS Base36
FROM    @Base10ToBase36 AS pos0
        CROSS JOIN @Base10ToBase36 AS pos1
ORDER BY NEWID()    -- random

About random you can get more explanation here: Random record from a database table (T-SQL)

Regarding primary key - I'm totally agree with @TheImpaler. It's bad idea