【单选题】下列哪个是 C++ 语言的合法的字符常量 ___ 。
【单选题】给出以下五个结论: 1 ; 2 ; 3 ; 4 ; 5 .其中正确结论的个数为( )
【单选题】查询student表中所有非空email信息,以下语句正确的是()
A.
SELECT email FROM student WHERE email != null
B.
SELECT email FROM student WHERE email not is null
C.
SELECT email FROM student WHERE email<>null
D.
SELECT email FROM student WHERE email is not null
【判断题】正常工作的凸轮机构中的凸轮和从动件不一定始终保持接触。
【简答题】[A] the waiter [ B ] time [C] I [D] the dinner
【单选题】查询student表中的所有非空email信息, 以下语句正确的是()
A.
Select email from student where email !=null
B.
Select email from student where email not is null
C.
Select email from student where email <> null
D.
Select email from student where email is not null