Repeat Exercise 16.3.3, but allow the sub query to be corollated with R. For simplicity, you may assume that the subquery has the simple form of select-from-where expression described in this section, with no further subqueries.
Exercise 16.3.3
Give a rule for converting each of the following forms of to relational algebra. All conditions may be assumed to be applied (by a two-argument selection) to a relation R. You may assume that the
subquery is not correlated with R. Be careful that you do not introduce or eliminate duplicates in opposition to the formal definition of SQL.
a) A condition of the form EXISTS ().
b) A condition of the form a - ANY , where a is an attribute of R.
c) A condition of the form a - ALL , where a is an attribute of R.