MySQL - Window Functions MCQ

MySQL – Window Functions MCQ

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1. What are MySQL window functions used for?

Database installation

Backup and recovery

Complex analytical calculations

Creating tables and indexes

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2. Which clause is used to define the window frame for a window function in MySQL?

WINDOW FRAME

ORDER BY

PARTITION BY

OVER()

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3. What does the RANK() window function do in MySQL?

Divides the result set into buckets

Calculates moving averages

Assigns a unique integer to each row

Assigns a rank to each row

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4. In MySQL window functions, what does the NTILE(n) function do?

Assigns a rank to each row

Calculates the sum of values

Divides the result set into "n" parts

Returns the first value within a window

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5. How are rows within a partition ordered when using MySQL window functions?

Randomly

Based on the ORDER BY clause

Alphabetically by column name

In reverse order of insertion

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6. Which window function can be used to calculate moving averages in MySQL?

AVG()

LEAD() or LAG()

SUM()

ROW_NUMBER()

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7. What is the primary use case for ROW_NUMBER() in MySQL window functions?

Assigning ranks

Selecting a specific range of rows

Performing mathematical calculations

Calculating moving averages

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8. Which window function assigns the same rank to identical values in MySQL?

LEAD()

SUM()

RANK()

NTILE()

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9. What is the purpose of the PARTITION BY clause in MySQL window functions?

To order rows within a partition

To calculate cumulative totals

To divide the result set into partitions

To define the window frame

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10. Which window function is suitable for assigning unique integers to rows within a partition?

DENSE_RANK()

SUM()

FIRST_VALUE()

ROW_NUMBER()

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11. What does the LAG() function do in MySQL window functions?

Accesses the value of the previous row

Calculates moving averages

Accesses the value of the next row

Returns the first value within a window

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12. In MySQL, what is the primary purpose of the OVER() clause in window functions?

To filter rows within a partition

To define the window for calculations

To specify the order of rows

To define the window frame

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13. Which window function is used for ranking rows based on a specified column’s values?

NTILE()

SUM()

LEAD()

RANK()

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14. In the context of MySQL window functions, what is a window frame?

A graphical representation

A subset of rows within a partition

A physical window on the screen

A section of the database

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15. How can you calculate a moving average of values in MySQL window functions?

Using the PARTITION BY clause

Using the ROW_NUMBER() function

Using the AVG() function

Using the OVER() clause

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16. What is the purpose of the LEAD() function in MySQL window functions?

To access the value of the next row

To calculate cumulative totals

To access the value of the previous row

To assign unique integers to rows

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17. Which window function can be used to divide a result set into equal parts in MySQL?

LAG()

NTILE()

SUM()

FIRST_VALUE()

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18. In MySQL window functions, how does DENSE_RANK() differ from RANK()?

DENSE_RANK() assigns gaps

DENSE_RANK() does not exist

DENSE_RANK() assigns ranks

DENSE_RANK() assigns unique integers

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19. Which SQL clause defines the order of rows within a partition in MySQL window functions?

OVER()

ORDER BY

PARTITION BY

WINDOW FRAME

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20. What does the FIRST_VALUE() function return in MySQL window functions?

The last value within a partition

The last row within a partition

The first value within a window

The first row within a window

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21. What is the primary purpose of the ORDER BY clause in MySQL window functions?

To assign unique integers to rows

To filter rows within a partition

To define the window frame

To specify the order of rows

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22. Which window function can be used to assign the same rank to identical values in MySQL?

DENSE_RANK()

LEAD()

NTILE()

SUM()

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23. In MySQL window functions, how does RANK() differ from DENSE_RANK()?

RANK() assigns ranks

RANK() assigns unique integers

RANK() does not exist

RANK() assigns gaps

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24. What is the main advantage of using MySQL window functions over subqueries for analytical tasks?

Window functions are simpler

Subqueries are faster

Subqueries offer more flexibility

Window functions offer better performance

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25. Which window function can be used to calculate the sum of values within a window in MySQL?

LAG()

SUM()

AVG()

FIRST_VALUE()

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26. How can you calculate quartiles or percentiles using MySQL window functions?

By using the LAG() function

By using the NTILE() function

By using the SUM() function

By using the ROW_NUMBER() function

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