Final answer:
The false statement regarding the UNION operator in SQL is that it can only combine SELECT statements from the same table.
In reality, UNION can combine results from different tables if they have the same number of columns and corresponding data types.
Step-by-step explanation:
The student question pertains to the UNION operator in SQL, which is used to combine the results of two or more SELECT statements.
The false statement among the given options is the fourth one: The UNION operator can only be used to combine SELECT statements from the same table. This is not true as the UNION operator can be used to combine SELECT statements from different tables as long as the statements have the same number of columns and corresponding data types.
- It is correct that the UNION operator combines the results into a single result set.
- The requirement for the same number of columns and data types in all SELECT statements is also true.
- Another accurate point is that UNION removes duplicate rows from the result.
The correct statement in this case is statement number 4, which says that the UNION operator can only be used to combine SELECT statements from the same table is false. The UNION operator can actually be used to combine the results of SELECT statements from different tables as long as the number of columns and their data types are compatible with each other.
For example, let's say we have two tables: Table A and Table B. We can use the UNION operator to combine the results of two SELECT statements, one from Table A and another from Table B, as long as the number of columns and their data types match.
Switching between tables can be advantageous when you have data distributed across multiple tables and you want to retrieve a consolidated result set. This allows you to avoid redundant data and organize your data in a more meaningful way.