如何在表的下面验证上创建约束

Question

如何为表的以下验证创建约束 下面的查询应始终返回零行。

select Col1,Col2,count(*) from Table
  where Col2=1
group by Col1,Col2
having count(*)>1

为了更好地理解我也提供数据

1. 第2列值应只有1或0个值

2. Column2每个Column1值的值应始终为1，并且可能有多个0

   Column1 Column2     
   1       1       
   1       0       
   1       0       
   1       1   X   This is wrong. Reason: This combination should be unique (1,1)
   2       1       
   2       1   X   This is wrong. Reason: This combination should be unique (2,1)
   2       0       
   3       1       
   3       1   X   This is wrong. Reason: This combination should be unique (3,1)
   3       0       
   

Answer 1

这有效

create function f1()
returns int
begin
return(select 0  from Table1
  where Col2=1
group by Col1,Col2
having count(*)>1)

end
create table table1(Col1 int, Col2 int)
alter table table1 WITH NOCHECK add constraint ck_table1 check(dbo.f1()>0)