How to perform query optimization in sql server 2012.

You have to follow steps:

 

   You need to see execution plan of SQL query

   Then you need to find out bottleneck of the query

   Then you need to choose best way to perform better.

 

So you need tools to execute above process. You can use SQL Profiler(available on professional SSMS) to catch slow queries. Then you can use SQL tuning advisor to see what is the best way to resolve the problem.

 

Follow below links that may help you:

 

https://technet.microsoft.com/en-us/library/2007.11.sqlquery.aspx 

 

http://www.sql-server-performance.com/2013/sql-server-query-optimization-part-1/ 

 

https://www.codeproject.com/Articles/34372/Top-steps-to-optimize-data-access-in-SQL-Server 

 

https://www.codeproject.com/Articles/35665/Top-steps-to-optimize-data-access-in-SQL-Serv