Question: I am creating sql queries and I have read in one book that when using `NOT` operator or `LIKE` operators `Indexes` do not work. How much true this statement is. How can we avoid this if the statement is true. How a query should be made to do the same work avoiding these operators.

What all other areas are there in sql server where Indexes are deferred.

Answer: 
For like looks to this article:
 [SQL Performance - Indexes and the LIKE clause](http://myitforum.com/cs2/blogs/jnelson/archive/2007/11/16/108354.aspx)

For NOT operator using indexes will depend on particular query.
The search term you need to explore this issue in more depth is sargable. 

here is one article to get you started:
<http://www.sql-server-performance.com/tips/t_sql_where_p2.aspx>