Stored Procedures Vs. Views

I have used both but what I am not clear is when I should prefer one over the other. I mean I know stored procedure can take in parameters...but really we can still perform the same thing using Views too right ?

So considering performance and other aspects when and why should I prefer one over the other ?

Well, I'd use stored proc for encapsulation of code and control permissions better.

A view is not really encapsulation: it's a macro that expands. If you start joining views pretty soon you'll have some horrendous queries. Yes they can be JOINed but they shouldn't..

Saying that, views are a tool that have their place (indexed views for example) like stored procs.

The advantage of views is that they can be treated just like tables. You can use WHERE to get filtered data from them, JOIN into them, et cetera. You can even INSERT data into them if they're simple enough. Views also allow you to index their results, unlike stored procedures.

A View is just like a single saved query statement, it cannot contain complex logic or multiple statements (beyond the use of union etc). For anything complex or customizable via parameters you would choose stored procedures which allow much greater flexibility.

It's common to use a combination of Views and Stored Procedures in a database architecture, and perhaps for very different reasons. Sometimes it's to achieve backward compatibility in sprocs when schema is re-engineered, sometimes to make the data more manipulatable compared with the way it's stored natively in tables (de-normalized views).

Heavy use of Views can degrade performance as it's more difficult for SQL Server to optimize these queries. However it is possible to use indexed-views which can actually enhance performance when working with joins in the same way as indexed-tables. There are much tighter restrictions on the allowed syntax when implementing indexed-views and a lot of subtleties in actually getting them working depending on the edition of SQL Server.

Think of Views as being more like tables than stored procedures.

The main advantage of stored procedures is that they allow you to incorporate logic (scripting). This logic may be as simple as an IF/ELSE or more complex such as DO WHILE loops, SWITCH/CASE.