Final answer:
The keyword to join two tables that do not have a commonly named and defined column is c) CROSS JOIN, which creates a Cartesian product of the tables without needing a matching column.
Step-by-step explanation:
The keyword that can be used to join two tables that do not contain a commonly named and defined column is c) CROSS JOIN. A CROSS JOIN produces a Cartesian product of the two tables, meaning it combines each row of one table with each row of the other table. This type of join does not require the two tables to have a matching column; instead, it pairs every row from one table with every row from the other table.
By contrast, INNER JOIN, NATURAL JOIN, and OUTER JOIN (which includes LEFT OUTER JOIN, RIGHT OUTER JOIN, and FULL OUTER JOIN) require the two tables to have at least one pair of similarly named columns with compatible data types, which are used to match rows from one table to the other.
The keyword that can be used to join two tables that do not contain a commonly named and defined column is the CROSS JOIN.
The CROSS JOIN returns the Cartesian product of the two tables, which means that it combines every row from the first table with every row from the second table.
For example, if you have a table of students and a table of courses, a CROSS JOIN would combine each student with each course, resulting in a table that lists every possible combination of students and courses.