Which of the following joins is most appropriate for the analyst to use to create this database view?

A business analyst is using a client table and an invoice table to create a database view that shows clients who have not made purchases yet.

Which of the following joins is most appropriate for the analyst to use to create this database view?
A . INNER JOIN ON Client.Key = Invoice.Key
B . RIGHT JOIN ON Client.Key = Invoice.Key WHERE BY Client.Key IS NOLL
C . LEFT JOIN ON Client.Key = Invoice.Key
D . LEFT JOIN ON Client.Key = Invoice.Key WHERE BY Invoice.Key IS NOLL

View Answer

Answer: D

Explanation:

The join that is most appropriate for the analyst to use to create this database view is option D. This join uses the LEFT JOIN clause to combine the client table and the invoice table based on the matching values in the Key column. The WHERE clause filters out the rows where the Invoice. Key column is not null, meaning that the client has made a purchase. The result is a view that shows only the clients who have not made any purchases yet. The other options either do not produce the desired result or have syntax errors. For example, option A would show only the clients who have made purchases, option B would show only the invoices that do not have a matching client, and option C would show all the clients regardless of their purchase status.

Reference: CompTIA DataSys+ Course Outline, Domain 1.0 Database Fundamentals, Objective 1.2 Given a scenario, execute database tasks using scripting and programming languages.