Which SQL join returns all rows from the left table and matched rows from the right, with nulls where there is no match?

Which SQL join returns all rows from the left table and matched rows from the right, with nulls where there is no match?

• A. LEFT OUTER JOIN
• B. INNER JOIN
• C. RIGHT OUTER JOIN
• D. FULL OUTER JOIN

Answer: (A)

This tests how different joins shape the result set. A left outer join keeps every row from the left table and brings in matching rows from the right table. If there’s no match on the right, the right-side columns appear as nulls. That behavior exactly matches the prompt: all rows from the left table, with data from the right only when a match exists, and nulls where there isn’t a match.

Think of it like listing all customers and their orders. You want every customer shown, and for those who have orders you’ll see the order details; for customers without orders, the order fields will be null. That’s not how inner joins work—those require a match on both sides and would drop customers with no orders. Right outer joins flip which side is preserved, keeping all rows from the right instead, while full outer joins keep all rows from both sides.