教师表teacher的“职称”字段可能的取值为:教授、副教授、讲师和助教要查找职称为教授或副教授的教师,错误的语句是()
A. SELECT * FROM teacher WHERE 职称=教授 AND 职称=副教授;
B. SELECT * FROM teacher WHERE RIGHT(职称, 2)=教授;
C. SELECT * FROM teacher WHERE 职称 IN(教授, 副教授);
D. SELECT * FROM teacher WHERE 职称=教授 OR 职称=副教授;
有学生表,其结构为:student(学号,姓名,性别,年龄),查询所有年龄小于等于18岁的女同学、并按年龄降序排序生成新的表stud,正确的SQL命令是()
A. CREATE TABLE stud AS SELECT * FROM student WHERE 性别=女 AND 年龄<=18 ORDER BY 年龄 DESC;
B. CREATE TABLE stud AS SELECT * FROM student WHERE 性别=女 AND 年龄<=18 ORDER BY 年龄 DESC;
CREATE TABLE stud AS SELECT * FROM student WHERE 性别=女 AND 年龄<=18 ORDER BY 年龄 ASC;
D. CREATE TABLE stud AS SELECT * FROM student WHERE 性别=女 AND 年龄<=18 ORDER BY 年龄;