Sql 字符串自增列的实现

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

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

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

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

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