In SQL, what does INNER JOIN do?

In SQL, what does INNER JOIN do?

• A. Returns all rows from the left table.
• B. Creates a temporary table.
• C. Returns rows with matching keys in both tables.
• D. Returns rows with non-matching keys only.

Answer: (C)

INNER JOIN focuses on matching rows between two tables. It returns rows where the join condition finds corresponding rows in both tables and combines their columns into a single row. If a row in one table has no match in the other, that row is excluded from the result. For example, joining customers and orders on customer_id shows only customers who have placed orders, with their order details; customers without orders won’t appear. It’s not about returning all rows from one table (that would be a left or right join), nor about creating a temporary table by itself unless you store the result explicitly, and it doesn’t return non-matching rows only.

INNER JOIN focuses on matching rows between two tables. It returns rows where the join condition finds corresponding rows in both tables and combines their columns into a single row. If a row in one table has no match in the other, that row is excluded from the result. For example, joining customers and orders on customer_id shows only customers who have placed orders, with their order details; customers without orders won’t appear. It’s not about returning all rows from one table (that would be a left or right join), nor about creating a temporary table by itself unless you store the result explicitly, and it doesn’t return non-matching rows only.