How to Improve slow running query performance using an Index ?

I recently come across the situation where my query was running very slow. I written a perfect query with good inner join and with proper condition. Have a look at query and its executing plan.



As you can see in the image query takes 1.28 minute to execute successfully. And as you can see in the figure , cause for the problem is Clustered Index Scan on LotDetails Table.

See the image below to get the clear idea about Clustered Index Scan Cost in this query.



What I did was Created Non-clustered index on “SlipID” and added “Active” column into Included Columns.






After doing this when I run my query it took 0 second to execute successfully. And Clustered index scan is now turned into Index seek which is 3% of the total execution cost.



So use index as and when required to boost the performance of your T-SQL Query.

Please correct me if I am wrong anywhere. :)