フリー問題

問題文

A query joins two tables on columns that carry identical names. What does the USING clause provide?

選択肢

1. The USING clause names the matching columns shared by both tables, and the ON clause instead spells out the equality test between the two participating sides.
2. The USING clause names the sorted rows shared by both tables, and the ON clause instead spells out the equality test between the two participating sides.
3. The USING clause names the sorted rows shared by both tables, and the ON clause instead spells out the grouping level between the two participating sides.
4. The USING clause names the matching columns shared by both tables, and the ON clause instead spells out the grouping level between the two participating sides.