Which statement best describes an Outer Join?

Which statement best describes an Outer Join?

• A. A type of join where only matched records are returned.
• B. A type of join where all records from one table and related records from a related table appear in a result set.
• C. A method in object-oriented programming.
• D. A query optimization technique.

Answer: (B)

An outer join brings in all rows from one table and any matching rows from the related table. If there’s no match on the related side, the result still includes the row from the primary table, but with NULL values for the columns from the other table. This is useful when you want to see every record from one table regardless of whether there’s related data in the other table. For example, a left outer join between customers and orders returns every customer, with order details filled in where the customer has orders, and NULLs where the customer has no orders. There are variations like left, right, or full outer joins, depending on which side you want to preserve. This differs from returning only matched rows (inner join) and isn’t about programming paradigms or optimization techniques.

An outer join brings in all rows from one table and any matching rows from the related table. If there’s no match on the related side, the result still includes the row from the primary table, but with NULL values for the columns from the other table. This is useful when you want to see every record from one table regardless of whether there’s related data in the other table. For example, a left outer join between customers and orders returns every customer, with order details filled in where the customer has orders, and NULLs where the customer has no orders. There are variations like left, right, or full outer joins, depending on which side you want to preserve. This differs from returning only matched rows (inner join) and isn’t about programming paradigms or optimization techniques.