Converting nvarchar to float

I need some help here.
I converted sample [nvarchar](50) to float but when I tried to select value less than 4 for example it is not working.

here is the select
select, CONVERT(float, y.sample) as sample
 from dbo.tb1 y
 where y.sample < '4'
id      sample
49      2
80      2.95
31      27.75
14      14.69
66      2.69
86      0.56
01      16.55
17      2.57
48      13.1
60      2
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Lee SavidgeCommented:
You need to cast the where clause otherwise it will do a text evaluation.

select, CONVERT(float, y.sample) as sample
 from dbo.tb1 y
 where y.sample < cast('4' as float)


Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
LougaLoAuthor Commented:
thank you
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Microsoft SQL Server 2008

From novice to tech pro — start learning today.