2016年12月8日
How to get the mapping relationship between two columns in a table
摘要： If a table have column A and B Count(distinct A) as Da Count(distinct B) as Db Count(distinct A, B) as Dab The Da/Db<=Dab, this will be always true; 1 阅读全文
posted @ 2016-12-08 18:43 Researcher 阅读(118) 评论(0) 推荐(0) 编辑