Engineering Questions with Answers - Multiple Choice Questions
MCQs on Set Operations
1 - Question
The union operation is represented by
a) ∩
b) U
c) –
d) *
View Answer
Answer: b
Explanation: Union operator combines the relations.
2 - Question
The intersection operator is used to get the _____ tuples.
a) Different
b) Common
c) All
d) Repeating
View Answer
Answer: b
Explanation: Intersection operator ignores unique tuples and takes only common ones.
3 - Question
The union operation automatically __________ unlike the select clause.
a) Adds tuples
b) Eliminates unique tuples
c) Adds common tuples
d) Eliminates duplicate
View Answer
Answer: d
Explanation: None.
4 - Question
If we want to retain all duplicates, we must write ________ in place of union.
a) Union all
b) Union some
c) Intersect all
d) Intersect some
View Answer
Answer: a
Explanation: Union all will combine all the tuples including duplicates.
5 - Question
(SELECT course id FROM SECTION WHERE semester = ’Fall’ AND YEAR= 2009) EXCEPT (SELECT course id FROM SECTION WHERE semester = ’Spring’ AND YEAR= 2010);
This query displays
a) Only tuples from second part
b) Only tuples from the first part which has the tuples from second part
c) Tuples from both the parts
d) Tuples from first part which do not have second part
View Answer
Answer: d
Explanation: Except keyword is used to ignore the values.
6 - Question
For like predicate which of the following is true.
i) % matches zero OF more characters. ii) _ matches exactly one CHARACTER.
a) i-only
b) ii-only
c) i & ii
d) None of the mentioned
View Answer
Answer: a
Explanation:% is used with like and _ is used to fill in the character.
Explanation:% is used with like and _ is used to fill in the character.
7 - Question
The number of attributes in relation is called as its
a) Cardinality
b) Degree
c) Tuples
d) Entity
View Answer
Answer: b
Explanation: None.
8 - Question
_____ clause is an additional filter that is applied to the result.
a) Select
b) Group-by
c) Having
d) Order by
View Answer
Answer: c
Explanation: Having is used to provide additional aggregate filtration to the query.
Explanation: Having is used to provide additional aggregate filtration to the query.
9 - Question
_________ joins are SQL server default
a) Outer
b) Inner
c) Equi
d) None of the mentioned
View Answer
Answer: b
Explanation: It is optional to give the inner keyword with the join as it is default.
10 - Question
The _____________ is essentially used to search for patterns in target string.
a) Like Predicate
b) Null Predicate
c) In Predicate
d) Out Predicate
View Answer
Answer: a
Explanation: Like predicate matches the string in the given pattern.