Crowdly

3, 5, 1, 6

Use the following relations R and S to answer the question:

Compute π_{B, C}(R ⋈ S). Which of the following records will be in the result?

6, 4

5, 3

4, 3

5, 6

Use the following relations R and S to answer the question:

Compute R ⋈ S. Which of the following records will be in the result?

6, 4, 4, 1

2, 3, 3, 5

3, 3, 1, 6

3, 5, 3, 1

Which keyword names a calculated column in the SELECT list, as in salary/12 _____ monthlySalary?

ALIAS

BY

AS

INTO

Use the following relations R and S to answer the question:

Compute π_{B, C}(R ⋈ S). Which of the following records will be in the result?

6, 4

5, 3

4, 3

5, 6

Use the following relations R and S to answer the question:

Compute R ⋈ S. Which of the following records will be in the result?

6, 4, 4, 1

2, 3, 3, 5

3, 3, 1, 6

3, 5, 3, 1

Which tuple relational calculus expresses the following?

List the staff names who manage properties for rent in London.

{S | Staff(S) ˄ (∃P) (PropertyForRent(P) ˄ (P.staffNo = S.staffNo) ˄ P.city = ‘London’)}

{S | Staff(S) ˅ (∃P) (PropertyForRent(P) ˅ (P.staffNo = S.staffNo) ˅ P.city = ‘London’)}

{S.fName, S.lName | Staff(S) ˅ (∃P) (PropertyForRent(P) ˅ (P.staffNo = S.staffNo) ˅ P.city = ‘London’)}

{S.fName, S.lName | Staff(S) ˄ (∃P) (PropertyForRent(P) ˄ (P.staffNo = S.staffNo) ˄ P.city = ‘London’)}

✅

What does COUNT(*) count?

Only rows containing no null values.

Only distinct rows.

Only rows where the first column is not null.

All rows of a table, regardless of nulls or duplicate values.

✅

Which two clauses of a SELECT statement are mandatory?

FROM and ORDER BY

SELECT and FROM

✅

SELECT and WHERE

WHERE and GROUP BY

Use the following relations R and S to answer the question:

Compute R ⋈ S. Which of the following records will be in the result?

6, 4, 4, 1

2, 3, 3, 5

3, 3, 1, 6

3, 5, 3, 1