标签:mys select 去重 使用 union all pre sel 重复 teacher
union----合并结果集
select sName from students
union
select tName from Teachers;
select sName from students
union all
select tName from Teachers;
标签:mys select 去重 使用 union all pre sel 重复 teacher
原文地址:https://www.cnblogs.com/yanlzy/p/11909159.html