CBSE Class 12 Informatics Practices More On Sql Grouping Records and Table Joins MCQs

Question: Which of the following will give the same answer irrespective of the NULL values in the specified column:

a) MIN()

b) MAX()

c) SUM()

d) None of the above

Answer: C

Question: An aggregate function:

a) Takes a column name as its arguments

b) May take an expression as its argument

c) Both (a) and (b)

d) None of (a) and (b)

Answer: C

Question: HAVING is used in conjunction with

a) WHERE

b) GROUP BY clause

c) Aggregate functions

d) None of the above

Answer: B

Question: In the FROM clause of a SELECT statement

a) Multiple Column Names are specified.

b) Multiple table names are specified

c) Multiple Column Names may be specified.

d) Multiple table names may be specified.

Answer: D

Question: JOIN in RDBMS refers to

a) Combination of multiple columns

b) Combination of multiple rows

c) Combination of multiple tables

d) Combination of multiple databases

Answer: C

Question: Referential integrity

a) Must be maintained

b) Cannot be maintained

c) Is automatically maintained by databases

d) Should not be maintained

Answer: A

Question: Equi-join is formed by equating

a) Foreign key with Primary key

b) Each row with all other rows

c) Primary key with Primary key

d) Two tables

Answer: A

Question: A Primary key column

a) Can have NULL values

b) Can have duplicate values

c) Both (a) and (b)

d) Neither (a) nor (b)

Answer: D

Question: Primary Key of a table can be

a) Defined at the time of table creation only.

b) Defined after table creation only.

c) Can be changed after table creation

d) Cannot be changed after table creation

Answer: A

Question: Two SELECT commands in a UNION

a) Should select same number of columns.

b) Should have different number of columns

c) Both (a) and (b)

d) Neither (a) nor (b)

Answer: C