Question

A table in your data stores patient information has Patient ID and Patient Name fields. In which scenario would you need to use joins?

1) When you want to combine data from multiple tables based on a common field
2) When you want to sort the data in ascending order
3) When you want to filter the data based on a specific condition
4) When you want to calculate the average of a numeric field

Answer 1

Joins in database queries are used to combine data from multiple tables and are applicable in the scenario where there's a need to merge patient information using a common field between tables.

Step-by-step explanation:

To address the scenario involving patient information, where the table contains Patient ID and Patient Name fields, joins are necessary in scenario 1 when you want to combine data from multiple tables based on a common field. This is because joins allow you to merge rows from two or more tables by having a common identifier in both tables. Sorting data (scenario 2), filtering data based on a condition (scenario 3), or calculating an average of a numeric field (scenario 4) typically do not require the use of joins. These tasks can be performed on a single table without the need to combine data from additional sources.