Why Shoud i use LINQ when i have SQL Query ?

LINQ is designed to fill the gap that exists between traditional .NET, that offers strong typing, and a full Object-Oriented approach

LINQ introduces an easy-learning approach for querying and modifying data and can support querying various types of data sources including relational data, XML and in-memory data structures.

Hope this link might help you the advantages of Using LINQ

http://www.c-sharpcorner.com/UploadFile/c5c6e2/using-linq-in-net/