MadeEasy Test Series: Databases - Relational Algebra

Question

Comments

first query gives manager id of all the departements.

second query gives employee id of the employee which have dependents.

if third is a join then it gives manger id of mangers who have dependents

and then fourth query gives names of those managers,

hence,answer is B.

Answer 1

The first relational algebra query gives the MGRSSN of all departments.

The second one gives the ESSN of all employees who have dependents.

The set difference between A and B gives the MGRSSN of department managers who do not have any dependent.

Hence option C.