Sql 字符串自增列的实现

ALTER FUNCTION [dbo].[f_NextID](@tabname VARCHAR(50))
RETURNS char(8)
AS
BEGIN
DECLARE @charval CHAR(8)

IF LOWER(@tabname) ='B_Fee_Type'
    SELECT @charval=RIGHT(100000001+ISNULL(MAX(id),0),8) FROM  B_Fee_Type WITH(XLOCK,PAGLOCK)
ELSE
    SET @charval='00000001'
RETURN @charval
END

--在表中应用函数
CREATE TABLE tb(
id char(8) PRIMARY KEY DEFAULT dbo.f_NextBH('tb'),
col int)

--插入资料
BEGIN TRAN
INSERT tb(col) VALUES(1)
INSERT tb(col) VALUES(2)
INSERT tb(col) VALUES(3)
DELETE tb WHERE col=3
INSERT tb(col) VALUES(4)
INSERT tb(id,col) VALUES(dbo.f_NextBH('tb'),14)
COMMIT TRAN

--显示结果
SELECT * FROM tb
/*--结果
id col 
---------------- ----------- 
00000001 1
00000002 2
00000003 4
00000004 14
--*/