学号为11位，如果不足11位或多于11位，则拒绝输入
Sno nchar（10）怎么用约束实现
create rule [dbo].[f1] as @aa like '[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9]'
GO
------解决方案--------------------
- SQL code
ALTER TABLE [ta] WITH CHECK ADD CONSTRAINT [CK_ta_1] CHECK (([Sno] like '[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9]'))GOALTER TABLE [ta] WITH CHECK ADD CONSTRAINT [CK_ta] CHECK ((len([Sno ])<=(11)))GO