Final answer:
The SQL operations UNION, FULL OUTER JOIN, SELF JOIN, and NATURAL JOIN represent different types of SQL operations and cannot be achieved by a single operator. They include combining result sets, joining rows from multiple tables, and working with hierarchical data.
Step-by-step explanation:
The SQL operator that satisfies the conditions of UNION, FULL OUTER JOIN, SELF JOIN, and NATURAL JOIN is not a single operator because these represent different types of operations in SQL. UNION is used to combine the result sets of two or more SELECT statements. It removes duplicate records and the SELECT statements must have the same number of columns in the result sets with similar data types. FULL OUTER JOIN is used to combine rows from two or more tables based on a related column between them, showing all rows from both tables. If no match is found, NULL values are displayed for the unmatched columns. SELF JOIN is not an operator but a regular join where a table is joined with itself to query hierarchical data or compare rows within the same table. NATURAL JOIN is a type of join that automatically joins tables based on columns with the same names and compatible data types in both tables. However, it is often discouraged due to potential unexpected results, especially if the tables change over time.