以下是CLASS表中的数据: CLASS CLASS_ID CLASS_NA
题型:单项选择题
问题:
以下是CLASS表中的数据:
CLASS | |||
CLASS_ID | CLASS_NAME | HOURS_CREDIT | INSTRUCTOR_ID |
1 | Incroduction to Accouncting | 3 | 4 |
2 | Computer Basics | 3 | 1 |
3 | Tax Accouncing Principles | 3 | 4 |
4 | American History | 3 | 2 |
5 | Basic Engineering | 3 |
SELECT COUNT(instructor_id)
FROM class;
A.2
B.3
C.4
D.5
E.这个语句将不会成功地执行