Question

What statement is true about a field specified in the USING clause?

The column loses its table identity, so it cannot be referenced in the SELECT or any other clause.
The column does not lose its table identity, so it must be fully qualified when referenced in the SELECT or any other clause.
The column loses its table identity, so it does not need to be qualified when referenced in the SELECT or any other clause.
The column loses its table identity, so it must be fully qualified when referenced in the SELECT or any other clause.

Answer 1

The statement that is true about a field specified in the USING clause is (Option B). The column does not lose its table identity, so it must be fully qualified when referenced in the SELECT or any other clause.

When a column is specified in the USING clause of a query, it is used for the join condition and does not lose its table identity. Therefore, it needs to be fully qualified with the table name when referenced in the SELECT or any other clause of the query.