Final answer:
Tables in relational databases are merged using JOIN operations, while UNION operations are used to combine rows from multiple tables. INTERSECT and MINUS operations are not commonly used for merging tables.
Step-by-step explanation:
Tables in relational databases are merged using JOIN operations. JOIN operations combine rows from two or more tables based on a related column or key. There are different types of JOIN operations, such as INNER JOIN, LEFT JOIN, and RIGHT JOIN, which determine which rows are included in the merged result.
UNION operations, on the other hand, are used to combine rows from two or more tables into a single result, but they do not require a relationship between the tables. UNION operations stack rows on top of each other to create a single set of results.
INTERSECT and MINUS operations are not typically used for merging tables in relational databases. INTERSECT returns only the rows that are common to both tables, while MINUS returns the rows that are in one table but not in the other.