Oracle中 Union 中 ORA-12704:字符集不匹配问题的解决

错误原因

在使用Union 连接时，若A集合中某列为nvarchar2或nvarchar类型，而B表或者更多表对应的是varchar2或者是varchar类型时，则会报ORA-12704:字符集不匹配问题的解决

解决方法

to_char()函数

select a.id as ID,a.title as Title, a.apply_reason as applyReason from table1 aunion select b.id as ID , to_char(b.name) as Title ,  to_char(b.use) as applyReason from table2 b