您的EXEC在不同的上下文中执行，因此它不知道在原始上下文中已声明的任何变量.您应该能够使用临时表而不是表变量，如下面的简单演示所示.

Your EXEC executes in a different context, therefore it is not aware of any variables that have been declared in your original context. You should be able to use a temp table instead of a table variable as shown in the simple demo below.

create table #t (id int)

declare @value nchar(1)
set @value = N'1'

declare @sql nvarchar(max)
set @sql = N'insert into #t (id) values (' + @value + N')'

exec (@sql)

select * from #t

drop table #t