CASTing

Second question of day: what is the len of @c?

declare @c varchar(800)

set @c = N'hello' + replicate('-',800)
print len(@c)
print @c

Sorry - you were wrong

Correct answer: 800
Explanation:
The CAST to nvarchar(800) has a maximum 4000 character len. The CAST then to varchar(800) fits in that space, so the len is 800

CASTing

First question of day: what is the len of @c?

declare @c varchar(8000)

set @c = N'hello' + replicate('-',8000)
print len(@c)
print @c

You got it right!

Correct answer: 4000
Explanation:
The CAST to NVARCHAR(4000) means that the maximum len is 4000, then the cast to varchar(8000) allows more characters, but the string is already truncated.

declare @c varchar(800)
set @c = N'hello'

The CAST to nvarchar(800) has a maximum 4000 character len.