In a left join, which statement describes the result of the join?

In a left join, which statement describes the result of the join?

• A. All rows from left and matching rows from right
• B. All rows from right and matching rows from left
• C. Only rows that have matches
• D. All rows from both tables

Answer: (A)

A left join keeps every row from the left table and brings in matching data from the right table. If there isn’t a match, the left row still appears, but the right-side columns are NULL. So the result set includes all rows from the left table plus any matching rows from the right. This is why that description is the best fit. It’s not all rows from the right (that would be a right join), not only rows with matches (that would be an inner join), and not all rows from both tables (that would be a full outer join).

A left join keeps every row from the left table and brings in matching data from the right table. If there isn’t a match, the left row still appears, but the right-side columns are NULL. So the result set includes all rows from the left table plus any matching rows from the right. This is why that description is the best fit. It’s not all rows from the right (that would be a right join), not only rows with matches (that would be an inner join), and not all rows from both tables (that would be a full outer join).