How does SQL differentiate between columns with the same name in multiple tables during a query?

In SQL, when a query involves multiple tables that contain columns with the same name, the way to differentiate between these columns is by prefixing the column name with the respective table name. This approach clarifies which table the column belongs to, ensuring that there is no ambiguity for the database engine when processing the query.

For example, if two tables, "employees" and "departments," both have a column named "id," you would specify the columns in your query as "employees.id" and "departments.id." By doing so, SQL can accurately identify which "id" you are referencing, avoiding any conflict that could arise from the columns sharing the same name.

This method of prefixing helps maintain clarity and prevents confusion during data retrieval from multiple tables. It is a standard practice in database management, especially when performing JOIN operations, and is essential for ensuring the correctness of the results returned by a query.