根据日期自动生成编码系列号的实例

--以下代码生成的编号长度为12，前6位为日期信息，格式为YYMMDD，后6位为流水号。
--创建得到当前日期的视图
CREATE VIEW v_GetDate
AS
SELECT dt=CONVERT(CHAR(6),GETDATE(),12)
GO

--得到新编号的函数
CREATE FUNCTION f_NextBH()
RETURNS char(12)
AS
BEGIN
DECLARE @dt CHAR(6)
SELECT @dt=dt FROM v_GetDate
RETURN(
SELECT @dt+RIGHT(1000001+ISNULL(RIGHT(MAX(BH),6),0),6)
FROM tb WITH(XLOCK,PAGLOCK)
WHERE BH like @dt+'%')
END
GO

--在表中应用函数
CREATE TABLE tb(
BH char(12) PRIMARY KEY DEFAULT dbo.f_NextBH(),
col int)

--插入资料
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(BH,col) VALUES(dbo.f_NextBH(),14)

--显示结果
SELECT * FROM tb
/*--结果
BH col
------------------- -----------
050405000001 1
050405000002 2
050405000003 4
050405000004 14
--*/

-----------------------------------------------

--根据输入类别自动生成编号示例

--表
create table tab(a varchar(20),b varchar(100))
go

--触发器
create trigger tr_insert on tab
instead of insert
as
declare @dt varchar(10)
set @dt='-'+convert(varchar(10),getdate(),120)

select * into #t
from inserted a join(
select gid_new=b.a,sid_new=1000001+isnull(max(cast(right(a.a,5) as int)),0)
from tab a
right join inserted b on charindex(b.a+@dt,a.a)=1
group by b.a
)b on a.a=b.gid_new
order by b.gid_new

declare @nid varchar(100),@a int
update #t set @a=case @nid when gid_new then @a+1 else sid_new end
,a=gid_new+@dt+'-'+right(@a,5)
,@nid=gid_new

insert tab select a,b from #t
go

--插入数据
insert tab values('sj','2222')
insert tab select 'sj','324324'
union all select 'sj','33343'
union all select 'dj','33343'
union all select 'dj','24324'
union all select 'sj','24234'

--显示插入结果
select * from tab order by a
go

--删除测试
drop table tab

/*--测试结果

a b
-------------------- --------
dj-2004-07-1-00001 33343
dj-2004-07-1-00002 24324
sj-2004-07-1-00001 2222
sj-2004-07-1-00002 324324
sj-2004-07-1-00003 33343
sj-2004-07-1-00004 24234

（所影响的行数为 6 行）
--*/