ProceduralThis language has fundamental and other operations which are used on relations .

Sigma (Greek)The select operation selects tuples that satisfy a given predicate.

Set-differenceThe expression r - s produces a relation containing those tuples in r but not in s.

None of the mentionedThe fundamental operations are select, project, union, set difference, Cartesian product, and rename.

Predicates, relation

Generalized selectionGeneralization Selection takes only one argument for operation.

All of the mentionedThe FULL OUTER JOIN keyword combines the result of both LEFT and RIGHT joins.

All of the mentionedThe FULL OUTER JOIN keyword combines the result of both LEFT and RIGHT joins.

Equijoins

Left to rightThe expression is evaluated from left to right according to the precedence.