Question

Relation algebra query that finds customer's who have a balance more than 1000, from deposit table is:
1. π balance > 1000 (σ customer_name(Deposit))
2. σ customer_name (π balance > 1000 (Deposit))
3. π customer_name (σ  balance > 1000 (Deposit))
4. σ  balance > 1000 (π customer_name (Deposit)

Answer 1

Correct Answer - Option 3 : π customer_name (σ  balance > 1000 (Deposit))

π customer_name (σ  balance > 1000 (Deposit)) will be the correct answer

Customer_id	Customer_name	Balance
1	Suvarna	2000
2	Richa	1000
3	Deepu	900
4	Ankit	3000

Important Points

Project Operation (π)

It projects column(s) that satisfy a given predicate.

Notation − πA1, A2, An (r)

Where A1, A2 , An are attribute names of relation r.

Duplicate rows are automatically eliminated, as the relation is a set.

Select Operation (σ)

It selects tuples that satisfy the given predicate from a relation