【单选题】在信息系统结构的四个层次中,以多媒体等丰富的形式向用户展现信息的是________。
【单选题】在数据库表employee中查找字段empid中以两个数字开头第三个字符是下画线”_"的所有记录,请问下列哪条语句是正确的( )
A.
select * from employee where empid like '[0-9][0-9]_%'
B.
select * from employee where empid like '[0-9][0-9]_[%]'
C.
select * from employee where empid like '[0-9]9[_]%'
D.
select * from employee where empid like '[0-9][0-9][_]'
【简答题】中国从南至北呈现出赤道带、热带、亚热带、暖温带、温带、寒温带六个温度带;降水量从东南向西北逐渐减少,各地年平均降水量差异很大。( )
【单选题】在数据库表employee中查找字段empid中以两个数字开头且第三个字符是下画线“_”所有记录。以下语句正确的是( )
A.
SELECT * FROM employee WHERE empid LIKE ‘[0-9][0-9]_%’
B.
SELECT * FROM employee WHERE empid LIKE ‘[0-9][0-9]_[%]’
C.
SELECT * FROM employee WHERE empid LIKE ‘[0-9]9[_]%’
D.
SELECT * FROM employee WHERE empid LIKE ‘[0-9][0-9][_]%’
【单选题】在数据库表employee中查找字段empid中以两个数字开头第三个字符是下画线“_”的所有记录。请选择以下正确的语句( )。
A.
SELECT * FROM employee WHERE empid LIKE '[0-9][0-9]_%'
B.
SELECT * FROM employee WHERE empid LIKE '[0-9][0-9]_[%]'
C.
SELECT * FROM employee WHERE empid LIKE '[0-9]9[_]%'
D.
SELECT * FROM employee WHERE empid LIKE '[0-9][0-9][_]%'