SELECT on a MERGE table is like . . . . . . . .

Answer: Option A

This question is about how MySQL handles the SELECT statement when dealing with MERGE tables. A MERGE table is a special type of table that combines data from multiple underlying tables.

Imagine you have two tables: Table A and Table B. A MERGE table acts like a combined view of these two tables. When you run SELECT on a MERGE table, it's like looking at the data from both Table A and Table B as if they were one big table.

Now, let's look at the options:
Option A: UNION ALL - This combines data from multiple tables, including duplicates.
Option B: UNION - This combines data from multiple tables, but removes duplicates.
Option C: UNION DISTINCT - This is the same as UNION (removes duplicates).
Option D: JOIN - This combines data from tables based on a shared column.

The answer is Option A: UNION ALL.

Why? Because a MERGE table behaves like a UNION ALL operation, meaning it combines the data from its underlying tables without removing duplicates.