SQL Server - Create a custom auto-increment field

Question

I am trying to produce a custom auto-increment functionality in sql. my custom auto-incerement ID should be like below...

S1501.001

\"S\" i

Answer 1

The best solution is to use

• an ID INT IDENTITY(1,1) column to get SQL Server to handle the automatic increment of your numeric value
• a computed, persisted column to convert that numeric value to the value you need

So try this:

CREATE TABLE dbo.tblCompany
  (ID INT IDENTITY(1,1) NOT NULL PRIMARY KEY CLUSTERED,
   CompanyID AS 'S1501.' + RIGHT('000' + CAST(ID AS VARCHAR(3)), 3) PERSISTED,
   .... your other columns here....
  )

Now, every time you insert a row into tblCompany without specifying values for ID or CompanyID:

INSERT INTO dbo.tblCompany(Col1, Col2, ..., ColN)
VALUES (Val1, Val2, ....., ValN)

then SQL Server will automatically and safely increase your ID value, and CompanyID will contain values like S1501.001, S1501.002,...... and so on - automatically, safely, reliably, no duplicates.