【单选题】《中国药典》(2015年版)规定,旋光仪性能检定采用( )进行。
【单选题】原材料采购跟单的基本要求是:适当的交货( )、地点、质量、数量及价格。
【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。
【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