What is the difference between `WHERE` and `JOIN … ON` when filtering related tables?

Question

Advanced SQL Developer — Medium

What is the difference between `WHERE` and `JOIN … ON` when filtering related tables?

Accepted Answer

JOIN ... ON specifies the relationship condition for combining rows, while WHERE filters rows after the join. This distinction is crucial for OUTER JOINs: a condition in WHERE can turn a LEFT JOIN into an INNER JOIN by removing NULLs, but the same condition in ON preserves all left-table rows.