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Questions and Answers
What is the purpose of nested queries in SQL?
What is the purpose of nested queries in SQL?
- To update the database schema
- To write more complex retrieval queries (correct)
- To create a backup of the database
- To delete duplicate records
In SQL, what does the comparison operator IN evaluate to?
In SQL, what does the comparison operator IN evaluate to?
- TRUE if the value is one of the elements in the set of values (correct)
- The maximum value in the set
- The average of the set of values
- A count of the set of values
What does a NULL value represent in SQL?
What does a NULL value represent in SQL?
- An empty string
- An unavailable or withheld value (correct)
- A value that needs to be updated
- An attribute that is not applicable to the database
How does SQL handle comparisons involving NULL values?
How does SQL handle comparisons involving NULL values?
What is the main purpose of aggregate functions in SQL?
What is the main purpose of aggregate functions in SQL?
What kind of logic does SQL use to handle NULL values?
What kind of logic does SQL use to handle NULL values?
In SQL, what does the = ANY (or = SOME) operator do?
In SQL, what does the = ANY (or = SOME) operator do?
What does the HAVING clause apply to in SQL?
What does the HAVING clause apply to in SQL?
What does the WITH clause allow in SQL?
What does the WITH clause allow in SQL?
When is the CASE construct used in SQL?
When is the CASE construct used in SQL?
What is an example of a recursive operation in SQL?
What is an example of a recursive operation in SQL?
In SQL, what is the purpose of the = ALL operator?
In SQL, what is the purpose of the = ALL operator?
What does the GROUP BY clause do in SQL?
What does the GROUP BY clause do in SQL?
What does the HAVING COUNT (*) > 5 condition signify in SQL?
What does the HAVING COUNT (*) > 5 condition signify in SQL?
What role does the UNION operator play in SQL?
What role does the UNION operator play in SQL?
In SQL, what is the purpose of the RECURSIVE keyword in CTE (Common Table Expression)?
In SQL, what is the purpose of the RECURSIVE keyword in CTE (Common Table Expression)?
