Which set operations are used to combine results of two SELECT statements that are union compatible?

Which set operations are used to combine results of two SELECT statements that are union compatible?

• A. UNION
• B. INTERSECT
• C. UNION, INTERSECT, and EXCEPT
• D. ALL of the above

Answer: (C)

When two SELECT results are union compatible—meaning they return the same number of columns with compatible data types—you can blend them using set operations. The standard ones you can use are UNION, INTERSECT, and EXCEPT. UNION combines all distinct rows from both results, giving a combined list without duplicates. INTERSECT gives you only the rows that appear in both result sets. EXCEPT yields rows that are in the first result but not in the second. These are the standard ways to merge two result sets, which is why they’re the correct set of operations for this scenario. Note that while UNION ALL exists in many databases to preserve duplicates, it’s not part of the standard trio described here, so the statement focusing on the standard set operations is the best fit.

When two SELECT results are union compatible—meaning they return the same number of columns with compatible data types—you can blend them using set operations. The standard ones you can use are UNION, INTERSECT, and EXCEPT. UNION combines all distinct rows from both results, giving a combined list without duplicates. INTERSECT gives you only the rows that appear in both result sets. EXCEPT yields rows that are in the first result but not in the second. These are the standard ways to merge two result sets, which is why they’re the correct set of operations for this scenario. Note that while UNION ALL exists in many databases to preserve duplicates, it’s not part of the standard trio described here, so the statement focusing on the standard set operations is the best fit.