ORA-12704: character set mismatch字符集不匹配

在做兩個select語句的union all的過程中，爆出了這個問題，這兩個語句單獨執行都能順利執行

於是可能問題在系統面對A語句時生成的  int，char字段，B語句生成的int，varchar2字段

那么問題就簡單了，將其轉化成相同數據類型的數據即可。

create table t_test1(id number, name varchar2(100));
create table t_test2(id number ,name nvarchar2(100));
--------------------
select t.* from T_TEST1 t;
select t.* from T_TEST2 t;
--------------------
insert into t_test1 values(1,'nameFromTest1');
insert into t_test2 values(2,'nameFromTest2');
--------------------union all查詢
select id, name from t_test1
union all
select id, name from t_test2;

然可能工作中比較復雜，比如name字段是由若干內容拼成的，這樣系統就會自動判斷這個字段該屬於什么類型

 

解決辦法如下

---------------------解決辦法1  to_char  to_nchar
select id, name from t_test1
union all
select id, to_char(name) from t_test2;
----------------- to_nchar    cast      translate...using  將varchar2轉為nvarchar2
---------------------------------to_nchar
select id, to_nchar(name) from t_test1
union all
select id, name from t_test2;
----------------------------------cast
select id, cast(name as nvarchar2(100)) from t_test1
union all
select id, name from t_test2;

----------------------------------translate...using  2   nchar_cs
select id, translate(name using nchar_cs) from t_test1
union all
select id, name from t_test2;
----------------------------------translate...using  2 char_cs
select id, name  from t_test1
union all
select id, translate(name using char_cs) from t_test2;