单项选择题
下述语句的功能是将两个查询结果合并为一个结果,其中正确的是______。
A.select sno,sname, sage from student where sdept = "cs"Order by sageUnionselect sno, sname, sage from student where sdept = "is"Order by sage
B.select sno, sname, sage from student where sdept = "cs"Unionselect sno, sname, sage from student where sdept = "is"Order by sage
C.select sno, sname, sage from student where sdept = "cs"Unionselect sno, sname from student where sdept = "is"Order by sage
D.select sno, sname, sage from student where sdept = "cs"Order by sageUnionselect sno, shame, sage fron student where sdept = "is"