语句UPDATE student set name=’youjun’, grade=98.5的运行结果是
A. 更新student表中第一条记录
B. 出现语法错误
C. 更新student表中最后一条记录
D. 更新 student表中每一条记录
查看答案
下面选项中,能够更新表student中id值小于4的SQL语句是( )
ALTER TABLE student where id<4;
B. UPDATE student set grade=100 where id<4;
C. UPDATE student set grade=100 where id<=4;
D. UPDATE Table student set grade=100 where id<4;
下面SQL语句中,用于删除user表中id大于5的记录的语句是
A. DELETE FROM user where id>5;
B. DELETE FROM user set id>5;
C. DELETE user where id>5;
DELETE user set id>5;
下面关于DELETE与TRUNCATE语句删除记录的描述,正确的是
A. DELETE比TRUNCATE语句效率更高
B. TRUNCATE比DELETE语句效率更高
C. DELETE只能删除表中部分记录
DELETE只能删除表中全部记录
下面关于SQL语句truncate table user;的解释,正确的是
A. 查询user表中的所有数据
B. 与“delete from user;“完全一样
C. 删除user表,并再次创建user表
D. 删除user表