oracle sign函数解决大于小于的decode写法：https://blog.csdn.net/gahaya/article/details/8193026

如何用Pivot实现行列转换：https://www.cnblogs.com/ivictor/p/4664011.html

ORACLE统计分析函数：https://www.cnblogs.com/kkfish/p/5235615.html

oracle分析函数汇总:https://blog.csdn.net/cc_0101/article/details/80884076

ORACLE物化视图与视图区别:https://blog.csdn.net/loveyaqin1990/article/details/53219839