1) A modification query may cause rows in a view to disappear if a column in the WHERE clause of the view definition is changed by an UPDATE statement.

True

False

2)

A nested query cannot have multiple levels, i.e. you cannot have a nested query inside another nested query.

True

False

3)

Null values affect:

simple conditions involving comparison operators

compound conditions involving logical operators

all of the above

aggregate calculations and grouping