带UNION ALL的快速刷新物化视图前提条件比较严格
1.UNION ALL必须在顶层；
2.每个分支查询必须符合快速刷新条件；
3.必须包含标识列，即报错提示的内容；
4.不允许外连接、源端表等
如果只是2个表单纯union all，查询频率不高的情况下，建议建普通视图即可；
如果确实需要快速刷新的物化视图，参考我这个例子：

create table t071901 (c1 int primary key, c2 varchar(10));
create table t071902 (c1 int primary key, c2 varchar(10));

create materialized view log on t071901 with primary key;
create materialized view log on t071902 with primary key;

create materialized view mtv_0719 REFRESH FAST WITH primary key on commit
as
select c1, c2, 1 marker from t071901
union all
select c1, c2, 2 marker from t071902
;