Which code correctly produces a report of only the matches from the employee_donations and employees tables, including each column once?

Which code correctly produces a report of only the matches from the employee_donations and employees tables, including each column once?

• A. select Employee_ID, Qtr1, Qtr2, Qtr3, Name from employee_donations as d inner join employees as e on Employee_ID = Employee_ID
• B. select e.Employee_ID, Qtr1, Qtr2, Qtr3, Name from employee_donations as d inner join employees as e on d.Employee_ID = e.Employee_ID
• C. select * from employee_donations as d inner join employees as e on d.Employee_ID=e.Employee_ID
• D. select Employee_ID, Qtr1, Qtr2 from employee_donations as d join employees as e on d.Employee_ID = e.Employee_ID

Answer: (B)

The chosen answer is correct because it specifically selects the appropriate columns from both the employee_donations and employees tables while ensuring that each column appears only once in the report. The use of table aliases (d for employee_donations and e for employees) helps clarify which columns are being referenced, particularly when similar column names exist in both tables. By explicitly specifying e.Employee_ID, Qtr1, Qtr2, Qtr3, and Name, the query avoids duplication and ambiguity in the results that might arise from a traditional * selection. Additionally, the inner join condition directly links the two tables through their common Employee_ID, ensuring that only matched records appear in the result set. This method maintains clarity and efficiency, producing a concise set of output with the intended data points. Other options may introduce issues such as duplicating column names or not specifying the necessary columns adequately. While option C selects all columns, it does not filter for unique columns and may result in confusion due to potential name clashes. The other options fail to clearly identify the necessary columns or use joins incorrectly, leading to less optimal results.

The chosen answer is correct because it specifically selects the appropriate columns from both the employee_donations and employees tables while ensuring that each column appears only once in the report. The use of table aliases (d for employee_donations and e for employees) helps clarify which columns are being referenced, particularly when similar column names exist in both tables.

By explicitly specifying e.Employee_ID, Qtr1, Qtr2, Qtr3, and Name, the query avoids duplication and ambiguity in the results that might arise from a traditional * selection. Additionally, the inner join condition directly links the two tables through their common Employee_ID, ensuring that only matched records appear in the result set. This method maintains clarity and efficiency, producing a concise set of output with the intended data points.

Other options may introduce issues such as duplicating column names or not specifying the necessary columns adequately. While option C selects all columns, it does not filter for unique columns and may result in confusion due to potential name clashes. The other options fail to clearly identify the necessary columns or use joins incorrectly, leading to less optimal results.