Which relational algebra operation is used to filter rows based on a condition?

Correct option is B

The Selection operation in relational algebra is used to filter rows based on a condition. It is denoted by the symbol σ and operates on rows of a relation.
Example:
To select employees with salary greater than 50000: σsalary>50000 (employees)
Important Key Points:
1. Selection filters rows (horizontal slicing), while projection filters columns (vertical slicing).
2. Selection results in a subset of the original relation.
Knowledge Booster:
· Union: Combines tuples from two relations.
· Projection: Filters columns in a relation.
· Cartesian Product: Combines tuples from two relations without any condition.
· Join: Combines related tuples based on a common attribute.