如何在oracle下选出姓名字段中出现次数最多的50个字符?答:select count(substr(clientname,1,1)) as 姓,count(substr(clientname,2,1)) 名1,count(substr(clientname,3,1)) 名2 from table--单姓 union select count(substr(clientname,1,2)) as 姓,count(substr(clientname,3,1)) 名1,count(substr(clientname,4,1)) 名2 from table;--复姓...