1 --提取汉字，去掉非汉子数据
 2 
 3 --创建函数
 4 Create Or Replace Function f_Getch(Str Varchar2) Return Varchar2 Is
 5   i       Int;
 6   Sub_Str Varchar2(500);
 7   Str2    Varchar2(500);
 8   Str1    Varchar2(500);
 9   Len     Int;
10 Begin
11   Str2 := Str;
12   Select Length(Str2) Into i From Dual;
13   While i > 0 Loop
14     Select Substr(Str2, 1, 1) Into Sub_Str From Dual;
15     Select Lengthb(Sub_Str) Into Len From Dual;
16     If Len = 3 Then
17       Str1 := Str1 || Sub_Str;
18     End If;
19     Select Substr(Str2, 2, Length(Str2)) Into Str2 From Dual;
20     Select Length(Str2) Into i From Dual;
21   End Loop;
22   Return Str1;
23 End;
24 
25 
26 
27 --创建测试数据
28 create table tests(
29 name varchar2(200)
30 );
31 
32 insert into tests (name)
33 values('你a好，你1吃D饭S了s吗');
34 
35 
36 --测试函数
37 select f_Getch(name) from tests