How to resolve ambiguous column names when retrieving results?

When retrieving results in PHP and encountering ambiguous column names, you can use table aliases to specify which table the column belongs to. For example, instead of just selecting "column_name", you would select "table_alias.column_name" in your query. For example, if you have two tables, "table1" and "table2" with a column named "id", you could use the aliases "t1" and "t2" to specify which "id" column you are referencing in your query.

SELECT t1.id, t2.id FROM table1 t1, table2 t2;

You can also use the AS keyword to assign a table alias.

SELECT table1.id AS t1_id, table2.id AS t2_id FROM table1, table2;

It's also possible to use the MySQL USING clause to specify which column to join on when using JOIN command.

SELECT t1.id, t2.id FROM table1 t1 JOIN table2 t2 USING (id);