--引用皱建的
--自已做标识列的例子--流水号:日期+当日编号:--创建视图,得到当前日期(因为函数中不能使用getdate())
create view v_getdate as select dt=convert(varchar,getdate(),112)
go--创建得到最大id的函数
create function f_getid()
returns varchar(12)
as
begin
declare @id varchar(12),@dt varchar(8)
select @dt=dt from v_getdate
select @id=@dt+'-'+right(1001+isnull(right(max(id),3),0),3)
from tb where id like @dt+'-%'
return(@id)
end
go--创建表
create table tb(id varchar(20) default dbo.f_getid() primary key,name varchar(10))
go
/*--创建触发器,在删除表中的记录时,自动更新记录的id
create trigger t_delete on tb
AFTER delete
as
declare @id int,@mid int
select @mid=min(id),@id=@mid-1 from deleted
update tb set id=@id,@id=@id+1 where id>@mid
--*/
go--插入记录测试
insert into tb(name) values('张三')
insert into tb(name) values('张四')
insert into tb(name) values('张五')
insert into tb(name) values('张六')
insert into tb(name) values('张七')
insert into tb(name) values('张八')
insert into tb(name) values('张九')
insert into tb(name) values('张十')--显示插入的结果
select * from tb--删除部分记录
delete from tb where name in('张五','张七','张八','张十')--显示删除后的结果
select * from tbgo
--删除环境
drop table tb
drop view v_getdate
drop function f_getid
--自已做标识列的例子--流水号:日期+当日编号:--创建视图,得到当前日期(因为函数中不能使用getdate())
create view v_getdate as select dt=convert(varchar,getdate(),112)
go--创建得到最大id的函数
create function f_getid()
returns varchar(12)
as
begin
declare @id varchar(12),@dt varchar(8)
select @dt=dt from v_getdate
select @id=@dt+'-'+right(1001+isnull(right(max(id),3),0),3)
from tb where id like @dt+'-%'
return(@id)
end
go--创建表
create table tb(id varchar(20) default dbo.f_getid() primary key,name varchar(10))
go
/*--创建触发器,在删除表中的记录时,自动更新记录的id
create trigger t_delete on tb
AFTER delete
as
declare @id int,@mid int
select @mid=min(id),@id=@mid-1 from deleted
update tb set id=@id,@id=@id+1 where id>@mid
--*/
go--插入记录测试
insert into tb(name) values('张三')
insert into tb(name) values('张四')
insert into tb(name) values('张五')
insert into tb(name) values('张六')
insert into tb(name) values('张七')
insert into tb(name) values('张八')
insert into tb(name) values('张九')
insert into tb(name) values('张十')--显示插入的结果
select * from tb--删除部分记录
delete from tb where name in('张五','张七','张八','张十')--显示删除后的结果
select * from tbgo
--删除环境
drop table tb
drop view v_getdate
drop function f_getid
GO
Create proc p_datenum
@datenum numeric(12) output,
@dtime datetime output
as
begin
set nocount on
declare @date varchar(8) --日期的字符型
declare @maxnum varchar(4) --后4位数字的字符型
declare @max numeric(12) --全部numid数字型
declare @datenow varchar(8) --当前日期的字符型 set @datenow = convert(varchar(8),getdate(),112)
if (select count(numid) from t_001) = 0
begin
set @datenum = convert(numeric(12),@datenow+'0001')
end
if (select count(numid) from t_001) > 0
begin
select @max = max(numid) from t_001
set @date = left(convert(varchar(12),@max),8)
set @maxnum = right(convert(varchar(12),@max),4)
if convert(numeric(8),@datenow) <= convert(numeric(8),@date)
begin
set @datenum = convert(numeric(12),@date+@maxnum) + 1
end
if convert(numeric(8),@datenow) > convert(numeric(8),@date)
begin
set @datenum = convert(numeric(12),@datenow+'0001')
end
end
select @dtime = getdate()
set nocount off
endGO
As
begin
declare @i Int
select @i=max(ID)+1 from table
若记录行为空,则返回第一个编号,否则返回最新编号+1
if isnull(@i) select @i=1
insert into table (ID,日期) values(@i,getdate())
if @@error=0 return @i else return 0
end
应用时,若本过程返回大于0值,代表成功插入新行,否则为失败.
应为:Create Procdure RetMaxNo()