Multiple Choice Questions - SQL Joins - Set 5
1. The inner join is by far the most . . . . . . . . In fact, it’s also referred to as a common join, and was originally called a . . . . . . . . . . by E. F. Codd. The inner join returns only those rows that represent a match between the two data sets.
A) internal join, simple join
B) common join, natural join
C) natural join, common join
D) simple join, internal join
2. The nested loops join supports which of the following logical join operators.
A) Inner join
B) Right and full outer join
C) Cross join
D) Right semi-join and right anti-semi-join
3. A cartesian product is formed when:
A) A join condition is omitted
B) A join condition is invalid
C) All rows in the first table are joined to all rows in the second table
D) All of above
4. In general, the performance of a JOIN operation can be improved if the columns involved in the JOIN condition are indexed.
A) True
B) False
5. Whereas an . . . . . . . . contains only the intersection of the two data sets, an . . . . . . . extends the inner join by adding the non-matching data from the left or right data set.
A) self join, left outer join
B) cartesian join, inner join
C) outer join, inner join
D) inner join, outer join
6. An . . . . . . . . returns rows from one table that would not join with another table; these are the rows that would be NULL extended if we performed an outer join.
A) semi join
B) inner join
C) anti-semi join
D) self join
7. By merging the data using the join, the rest of the SQL SELECT statement, including the column expressions, aggregate groupings, and WHERE clause conditions, can access . . . . . . . . . .
A) any of the columns or rows from the joined tables.
B) columns only from the left table
C) columns only from the right table
D) none of above
8. A . . . . . . . can be nested inside an INNER JOIN, but an INNER JOIN cannot be nested inside a . . . . . .
A) SELF JOIN
B) NESTED JOIN
C) LEFT JOIN or a RIGHT JOIN
D) All of above
9. IF you attempt to join tables on columns of different data types, then the query will run faster as the Query Optimizer effectively uses indexes at this time.
A) True
B) False
10. Merge join supports full outer joins without an . . . . . . . . . predicate.
A) cross
B) null
C) equijoin
D) none of above
Answers
1. The inner join is by far the most . . . . . . . . In fact, it’s also referred to as a common join, and was originally called a . . . . . . . . . . by E. F. Codd. The inner join returns only those rows that represent a match between the two data sets.
A) internal join, simple join
B) common join, natural join
C) natural join, common join
D) simple join, internal join
2. The nested loops join supports which of the following logical join operators.
A) Inner join
B) Right and full outer join
C) Cross join
D) Right semi-join and right anti-semi-join
3. A cartesian product is formed when:
A) A join condition is omitted
B) A join condition is invalid
C) All rows in the first table are joined to all rows in the second table
D) All of above
4. In general, the performance of a JOIN operation can be improved if the columns involved in the JOIN condition are indexed.
A) True
B) False
5. Whereas an . . . . . . . . contains only the intersection of the two data sets, an . . . . . . . extends the inner join by adding the non-matching data from the left or right data set.
A) self join, left outer join
B) cartesian join, inner join
C) outer join, inner join
D) inner join, outer join
6. An . . . . . . . . returns rows from one table that would not join with another table; these are the rows that would be NULL extended if we performed an outer join.
A) semi join
B) inner join
C) anti-semi join
D) self join
7. By merging the data using the join, the rest of the SQL SELECT statement, including the column expressions, aggregate groupings, and WHERE clause conditions, can access . . . . . . . . . .
A) any of the columns or rows from the joined tables.
B) columns only from the left table
C) columns only from the right table
D) none of above
8. A . . . . . . . can be nested inside an INNER JOIN, but an INNER JOIN cannot be nested inside a . . . . . .
A) SELF JOIN
B) NESTED JOIN
C) LEFT JOIN or a RIGHT JOIN
D) All of above
9. IF you attempt to join tables on columns of different data types, then the query will run faster as the Query Optimizer effectively uses indexes at this time.
A) True
B) False
10. Merge join supports full outer joins without an . . . . . . . . . predicate.
A) cross
B) null
C) equijoin
D) none of above
Answers