Question 55

Using DISTINCT and WHERE statements allows for effective extraction of unique invoice IDs with amounts over $1,000.

The combination of DISTINCT and WHERE statements is ideal for retrieving unique entries that meet specific conditions, such as invoice amounts exceeding $1,000.

A) TRIM and COALESCE statements

TRIM and COALESCE are used for string manipulation and handling NULL values respectively, but they do not serve the purpose of filtering data based on a condition like invoice amounts. Therefore, this option does not address the requirement of extracting unique invoice IDs with a specified amount.

B) LENGTH and TRIM statements

LENGTH is typically used to determine the length of a string, while TRIM is used to remove whitespace. Neither of these functions assists in filtering or selecting data based on numeric conditions such as invoice amount, making this combination ineffective for the task.

C) DISTINCT and WHERE statements

This option is correct as the WHERE clause allows the analyst to specify that only invoices with amounts greater than $1,000 should be included, and DISTINCT ensures that the resulting invoice IDs are unique. This combination directly aligns with the requirements of the task.

D) ORDER BY and CONCAT statements

ORDER BY is used for sorting results, and CONCAT is used for string concatenation. These functions do not filter data based on specific conditions and therefore do not meet the task's objective of extracting unique invoice IDs based on a monetary threshold.

Conclusion

The option of using DISTINCT and WHERE statements is the only combination that effectively fulfills the requirement of extracting unique invoice IDs with amounts greater than $1,000. Other options, while useful in their contexts, fail to provide the necessary functionality for this specific data extraction task.