In a left anti join, which describes the result set?

In a left anti join, which describes the result set?

• A. It returns non-matching rows from the left table
• B. It returns all matching rows
• C. It returns non-matching rows from the right table
• D. It returns all rows from both tables

Answer: (A)

A left anti join returns rows from the left table that have no matching row in the right table according to the join condition. It filters the left side to keep only those rows with no corresponding match on the right. For example, if the left table has ids 1, 2, 3 and the right table has id 2, the left anti join on id would yield rows with id 1 and 3. This differs from a left join, which would include all left rows and fill in right-side data (or nulls when there’s no match). It also isn’t about returning non-matching rows from the right or all rows from both tables.

A left anti join returns rows from the left table that have no matching row in the right table according to the join condition. It filters the left side to keep only those rows with no corresponding match on the right. For example, if the left table has ids 1, 2, 3 and the right table has id 2, the left anti join on id would yield rows with id 1 and 3. This differs from a left join, which would include all left rows and fill in right-side data (or nulls when there’s no match). It also isn’t about returning non-matching rows from the right or all rows from both tables.