错误语句：select id,name from s1 order by stime union all select id,name from s2 order by stime
报错原因：oracle 搜索到order by后认为整个select语句就该结束了但是后面还有union all所以数据库无法解析，导致报错
处理办法：with a1 as (select id,name from s1 order by stime) , a2 as (select id,name from s2 order by stime) select * from a1 union all select * from a2