我有这个问题 select distinct a.addressID,a.StreetNumber,a.Street,a.StreetType,a.PostalCode
from Address ainner join UserAdress ca on a.addressID = ca.addressID addressID在所有情况下都是不同的,如果我删除addressID并查询表,我会得到唯一的记录但是如果我保留addressID并查询它,我会得到重复的记录。我看到userAddress表有2个条目,我想从中获得1个
.* from (select distinct emp.name from emp orderby emp.id order by emp.name) s
where rownum<=20; 问题:emp表非常大,包含数十亿行,还包含重复的记录。修改后的查询 select s.* from (select distinct emp.name from emp orderby emp.id where rownum<=20) order by s.name; 修改查询时出现问题: 如果假设检索