In a LEFT JOIN anti-join pattern, what does adding WHERE right_table.id IS NULL accomplish?

Question

SQL Data Analyst — Medium

In a LEFT JOIN anti-join pattern, what does adding WHERE right_table.id IS NULL accomplish?

Accepted Answer

In a LEFT JOIN anti-join pattern, adding WHERE right_table.id IS NULL filters out rows with no matching row in the right table. This helps identify rows from the left table that do not have corresponding records in the right table.