Module 1 Advanced Queries Chapter 7 Outline Quiz
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Questions and Answers

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?

  • 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?

  • 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?

    <p>It avoids comparisons involving NULL values (D)</p> Signup and view all the answers

    What is the main purpose of aggregate functions in SQL?

    <p>To group and summarize data in queries (A)</p> Signup and view all the answers

    What kind of logic does SQL use to handle NULL values?

    <p>Three-valued logic (C)</p> Signup and view all the answers

    In SQL, what does the = ANY (or = SOME) operator do?

    <p>Returns TRUE if the value is equal to some value in the set V and is equivalent to IN (C)</p> Signup and view all the answers

    What does the HAVING clause apply to in SQL?

    <p>Entire group of tuples (A)</p> Signup and view all the answers

    What does the WITH clause allow in SQL?

    <p>Defining a table that will only be used in a particular query (A)</p> Signup and view all the answers

    When is the CASE construct used in SQL?

    <p>When a value can be different based on certain conditions (D)</p> Signup and view all the answers

    What is an example of a recursive operation in SQL?

    <p>Retrieving all supervisees of a supervisory employee at all levels (A)</p> Signup and view all the answers

    In SQL, what is the purpose of the = ALL operator?

    <p>Returns TRUE if the value is equal to all values in the set V (A)</p> Signup and view all the answers

    What does the GROUP BY clause do in SQL?

    <p>Groups rows that have the same values into summary rows (D)</p> Signup and view all the answers

    What does the HAVING COUNT (*) > 5 condition signify in SQL?

    <p>It filters groups where there are more than 5 rows after grouping (D)</p> Signup and view all the answers

    What role does the UNION operator play in SQL?

    <p>Combines result sets from two or more SELECT statements into a single result set (D)</p> Signup and view all the answers

    In SQL, what is the purpose of the RECURSIVE keyword in CTE (Common Table Expression)?

    <p>To define a CTE that can call itself within its own definition (D)</p> Signup and view all the answers

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