GATE 2022: Database Management system Quiz-4

Identify the capabilities of SELECT statement.

1. Projection
2. Selection
3. Data Control
4. Transaction

Consider the following Relational Schema:

Sailors (sid: integer, sname: string, rating: integer, age: real)

Boats (bid: integer, bname: string, color: string)

Reserves (sid: integer, bid: integer, day: date)

Consider the Following Statements:

S1:SELECT S.sname

FROM Sailors S

WHERE NOT EXISTS (SELECT *

FROM Sailors S2

WHERE S2.age < 21 AND S.rating <= S2.rating )

S2: SELECT S.sname

FROM Sailors S

WHERE S.rating > ANY (SELECT S2.rating

FROM Sailors S2

WHERE S2.age < 21 )

Which of the following is true regarding S1 and S2?

How many rows will be there in output of the following query for the data given below:

Employee

Teaches

Select *

from Employee

Where exists( select count(*)) from teaches

where Cname = 'CO'

Consider the following table-

Now consider the following query-

Select name from student where P>80 and M<50;

Number of Output after executing above query will be: