Varchar(max) column not allowed to be a Primary Key in SQL Server

Question

Varchar(max) column not allowed to be a Primary Key in SQL Server.

What is the max length of a varchar type that can be made a primary key.

This might be a b

Answer 1

The primary key is used in all other indexes to identify rows. Having a potentially multi-megabyte value as a key makes very little sense, hence the limit in general on total bytes in any key.