在“职工”表中有姓名、性别和生日等3个字段,要查询所有年龄大于50岁职工的姓名、性别和年龄,正确的SQL命令是
A. SELECT姓名,性别,YEAR(DATE())-YEAR([生日]) AS 年龄 FROM 职工 WHERE YEAR(Date())-YEAR([生日])>50
B. SELECT姓名,性别,YEAR(DATE())-YEAR([生日]) 年龄 FROM 职工 WHERE YEAR(Date())-YEAR([生日])>50
C. SELECT姓名,性别,YEAR(DATE())-YEAR([生日]) AS 年龄 FROM 职工 WHERE 年龄>50
D. SELECT姓名,性别,YEAR(DATE())-YEAR([生日]) 年龄 FROM 职工 WHERE 年龄>50
从“产品”表中查找出单价低于“产品编号”为“431”的记录所对应单价,正确的SQL命令是
A. SELECT * FROM 产品 WHERE 单价<"431"
B. SELECT * FROM 产品 WHERE EXISTS 单价="431"
C. SELECT * FROM 产品 WHERE 单价
D. SELECT * FROM 产品 WHERE 单价 <(Select 单价 From 产品 Where 产品编号="431")