where col like N'%�%'

why do you think,you need N prefix：

Prefix Unicode character string constants with the letter N. Without the N prefix,the string is converted to the default code page of the database. This default code page may not recognize certain characters.

感谢马丁·史密斯,早些时候我只测试了一个字符,它的工作,但正如马丁指出,它返回所有字符..

以下查询工作和返回只有意图

select * from #demo where id  like N'%�%' 
COLLATE Latin1_General_100_BIN

演示：

create table #demo
(
id nvarchar(max)
)

insert into #demo
values
(N'ﬗ'),( N'�')

要了解更多关于unicode,请看下面的链接

http://kunststube.net/encoding/

https://www.joelonsoftware.com/2003/10/08/the-absolute-minimum-every-software-developer-absolutely-positively-must-know-about-unicode-and-character-sets-no-excuses/