Master SQL for Data Analysis - Ranking

The video tutorial explains how to partition rows and assign sequential numbers. It addresses the issue of ranking rows with duplicate values and introduces the rank function as a solution. The rank function assigns ranks within partitions and handles duplicate values by skipping rank numbers. An example demonstrates the syntax and usage of the rank function.

What is the main issue with using sequential numbers for rows with the same value?

• They are difficult to implement.

• They are not useful for any use case.

• They can differ even if the rows have the same value.

• They are always the same for all rows.

Which window function can be used to assign the same rank to rows with the same value?

• Partition

• Rank

• Dense Rank

• Row Number

What is the syntax used to implement the rank function?

• SELECT RANK() OVER (PARTITION BY column ORDER BY column) FROM table

• SELECT * FROM table ORDER BY rank

• SELECT * FROM table GROUP BY rank

• SELECT * FROM table WHERE rank = 1

What happens when the rank function encounters rows with the same value?

• It skips rank numbers for subsequent rows.

• It assigns different ranks to each row.

• It assigns a random rank to each row.

• It assigns the same rank to all such rows.

Why might you choose to use the rank function over sequential numbering?

• To avoid using partitions.

• To make the query run faster.

• To assign the same number to rows with the same value.

• To ensure all rows have unique numbers.