I am trying to write the following query using the relational algebra:\[code\]"Find the names of sailors who reserved a red or a green boat"\[/code\]Here is my solution:
But the book gives the following solution:
And another equivalent solution given by book:
End here is the related tables:
My question is, can't we use the "or" symbol (V) in selection operator? Is my solution wrong? Why do we need renaming operator?Thanks