国开 / MySQL数据库应用
员工表staff表结构如下
staffNo varchar2(10),
Email varchar2(50)
哪一个SQL语句能查询出没有E_mail地址的员工号（ ）。
select staffno from Staff where Email = NULL
select staffno from Staff where Email <> NULL
select staffno from Staff where Email is null
select staffno from Staff where Email is not null
staffNo varchar2(10),
Email varchar2(50)
哪一个SQL语句能查询出没有E_mail地址的员工号（ ）。
select staffno from Staff where Email = NULL
select staffno from Staff where Email <> NULL
select staffno from Staff where Email is null
select staffno from Staff where Email is not null
参考答案：
佳题速递：