递增数据插入表(二）

递增数据插入表，我们还可以使用生成随机数来填充，建表的时候使用约束，不能重复，重复的话自然就不插入，继续生成下一个不重复的随机数。

还是以之前的为例，插入表中的数据为100-999。我们不谈性能（插入数据量小速度也很快的），只谈逻辑。

create table TestNum(num numeric(3,0) unique,check (num between 100 and 999));
go
declare @num int
set @num=(select COUNT(*) from TestNum)
while (@num < 900) 
begin
insert into TestNum 
select round(RAND(CHECKSUM(newid()))*1000,0)
set @num = (select count(*) from TestNum)
end;
go
select COUNT(*) from TestNum;
go
select * from TestNum order by 1;
go

上面的插入可能只是某个需求中最基础的实现，比如下面的111000到111999，前面111不变，后面的改变。实际应用可以生成特定号码段的号码

create table TestNum(num numeric(6,0) unique,check (num between 111000 and 111999));
go
declare @num int
set @num=(select COUNT(*) from TestNum)
while (@num < 1000) 
begin
insert into TestNum 
select cast('111'+right('000'+convert(nvarchar(6),round(RAND(CHECKSUM(newid()))*1000,0)),3) as numeric(6,0))
set @num = (select count(*) from TestNum)
end;
go