陈述A:SubQuery1 UNION SubQuery2语句,要求在执行该运算时参与运算的查询结果的列数一样,其对应列的数据类型必须一致。陈述B:GROUP BY和HAVING子句不能在子查询中使用,这些子句只能用在最后一个查询结束总结和排序最后结果集。关于陈述A和B,下列说法正确的是_________。
A.
陈述 A 正确,陈述 B 错误
B.
都是正确的
C.
都是错误的
D.
陈述 A 错误,陈述 B 正确
拍照语音搜题,微信中搜索"皮皮学"使用
参考答案:
参考解析:
知识点:
皮皮学刷刷变学霸
举一反三
【简答题】A. It doesn't have any cooperation with other companies.B. It has limited kinds of software products.C. The after-sales team isn’t effective and qualified.D. It doesn’t adopt an appropriate marketing ...
【简答题】There are many different approaches to developing and implementing change and each company tries to adopt the most appropriate model for their needs and requirements. The following diagram represents ...