The ∏ operator is used for projection, which selects specific attributes from a relation.
Projection using the ∏ operator has the following general syntax:
π attributes(Relation).
π represents the projection symbol (pi).
attributes are the columns from the relation.
Consider the relation PASSENGERS, which has attributes such as ID, Name, Age, and SeatNo. To choose only the ID and Name attributes from this relation, we may use the projection operation described below:
π ID, Name (Passengers)
This operation creates a new relation with only the ID and Name columns from the original PASSENGERS relation.