When we query a table, we have different ways to query it to get the same result. We have seen this in the example of retrieving the student details who are in DESIGN_01 class. Though the SQL is written in a single way, the DBMS can interpret it in different ways to identify better execution path. Now let us see what the different types of selection methods we have are and how they are affecting the cost of the query.
1. File Scan
2. Index Scan