How do we estimate the size for an inequality comparison in a relation S?
Given a scenario below:
There are 10,000 students records stored in 1,000 blocks.
The student ages range from 7 to 24.
What is the estimated size after performing selection on 12 < age < 20?
From what I have learnt, if it is inequality comparison, the formula is T(S) * 1/3. In this case, do we break it down to age > 12 and age < 20 and hence, it is T(S) * 1/3 * 1/3?
Thank you for your help. I am still new to RDBMS and trying to learn about estimating the size for a query execution plan.
