单项选择题
在MySQL 中,如果在代码DELETE FROM student WHERE s_id >5中,取消WHERE s_id >5,仅执行DELETE FROM student ,其结果意味着()。
A.删除表student
B.删除表student的所有记录
C.删除数据库student
D.语句不完整,不能执行
相关考题
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单项选择题
在MySQL 中,语句:DELETE FROM Employee 的作用是()。
A.删除当前数据库中整个Employee 表,包括表结构
B.删除当前数据库中Employee 表内的所有行
C.由于没有WHERE 子句,因此不删除任何数据
D.删除当前数据库中Employee 表内的当前行 -
单项选择题
在MySQL 中,查询姓名不是NULL 的语法正确的是()。
A.WHERE NAME <>NULL
B.WHERE NAME NOT IS NULL
C.WHERE NAME IS NOT NULL
D.WHERE NAME !=NULL -
单项选择题
已知某MySQL 数据库中,有表及其字段如下:Employee(员工)表,字段:ID(标识,主键)、Name(姓名)、DepartmentID(班级标识,外键)Department(部门)表,字段:ID(标识,主键)、Name(名称)要查询各部门人数(包括空部门),可以使用的查询语句是()。
A.SELECT Department.Name,COUNT(Employee.ID)’班级人数’FROM Department RIGHT JOIN Employee WHERE Department.ID =Employee.DepartmentID GROUP BY Department.Name,Employee.DepartmentID
B.SELECT Department.Name,COUNT(Employee.ID)’班级人数’FROM Department RIGHT JOIN Employee ON Department.ID =Employee.DepartmentID GROUP BY Department.Name,Employee.DepartmentID
C.SELECT Department.Name,COUNT(Employee.ID)’班级人数’FROM Department LEFT JOIN Employee WHERE Department.ID =Employee.DepartmentID GROUP BY Department.Name,Employee.DepartmentID
D.SELECT Department.Name,COUNT(Employee.ID)’班级人数’FROM Department LEFT JOIN Employee ON Department.ID =Employee.DepartmentID GROUP BY Department.Name,Employee.DepartmentID