执行下列程序的输出结果为()public class Test {public static void main(String[] args) { String s1 = HelloWorld; String s2 = new String(HelloWorld); if (s1 == s2) { System.out.println(s1 == s2); } else { System.out.println(s1 != s2); } if (s1.equals(s2)) { System.out.println(s1 equals s2); } else { System.out.println(s1 not equals s2); } }}
A.s1 == s2s1 not equals s2
B.s1 == s2s1 equals s2
C.s1 != s2s1 not equals s2
D.s1 != s2s1 equals s2
快件信息表waybillinfo(id, waybillno, zonecode, optype, update_time)中存储了快件的所有操作信息,请找出在中山公园网点,异常派送(optype=异常派件)次数超过3次的快件(waybillno),正确的sql为()(2.5分)
A.select waybillno, count(*) from waybillinfo where zonecode=中山公园 and optype=异常派件 and count(waybillno) 3
B.select waybillno, count(*) from waybillinfo where zonecode=中山公园 and optype=异常派件 order by waybillno having count(*) 3
C.select waybillno, count(*) from waybillinfo where zonecode=中山公园 and optype=异常派件 having count(*) 3
D.select waybillno from waybillinfo where zonecode=中山公园 and optype=异常派件 group by waybillno having count(*) 3
有订单表orders,包含字段用户信息userid,字段产品信息productid,以下语句能够返回至少被订购过两次的productid?()(2.5分)
A.select productid from orders where count(productid)1
B.select productid from orders where max(productid)1
C.select productid from orders where having count(productid)1 group by productid
D.select productid from orders group by productid having count(productid)1