フリー問題

問題文

A report filters a field with the test phone = NULL, and some records in that field hold no data. What does the query hand back?

選択肢

1. The query therefore hands back an automatic type widening when the engine finishes that scan.
2. The query therefore hands back an instant parse error when the engine finishes that scan.
3. The query therefore hands back an empty result set when the engine finishes that scan.
4. The query therefore hands back an assumed true condition when the engine finishes that scan.