Data Aggregation interview questions
Data Aggregation interview questions
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Total Questions: 10
1. Which of the following is not a aggregate function ?
Correct Answer is : With
2. The phrase “greater than at least one” is represented in SQL by ___________
Correct Answer is : > some
3. Aggregate functions are functions that take a ___________ as input and return a single value.
Correct Answer is : Collection of values
4. SQL applies predicates in the _______ clause after groups have been formed, so aggregate functions may be used.
Correct Answer is : With
5. The ________ keyword is used to access attributes of preceding tables or subqueries in the from clause.
Correct Answer is : Lateral
6. If we do want to eliminate duplicates, we use the keyword __________in the aggregate expression.
Correct Answer is : Distinct
7. All aggregate functions except __________ ignore null values in their input collection.
Correct Answer is : Count(attribute)
8. A Boolean data type that can take values true, false, and ____________
Correct Answer is : Unknown
9. Which of the following should be used to find all the courses taught in the Fall 2009 semester but not in the Spring 2010 semester ?
Correct Answer is : SELECT DISTINCT course id
FROM SECTION
WHERE semester = ’Fall’ AND YEAR= 2009 AND
course id NOT IN (SELECT course id FROM SECTION WHERE semester = ’Spring’ AND YEAR= 2010);
10. We can test for the nonexistence of tuples in a subquery by using the __________ construct.
Correct Answer is : Not exists
