Oracle字符串截取和拼接应用

今天有人问了个关于Oracle字符串截取和拼接的问题，让我帮他写出SQL，看了下问题描述还比较清晰就试着解决下，利用午休时间把功能实现了，问题看似不难，但思路一定要清晰，不然就乱了，关键大量应用了Oracle的substr 和instr函数，下面贴出问题和脚本：

问题：sql中一个字段值为：1788987565327、768374872394903、21437238740213483874629、23412341234252345。其中顿号间隔的每一组数字位数和尾数不定，现在要使前面这个字段值中顿号前的数字尾数即7、3、9、5都分别加1，变成8、4、0、6输出成1788987565328、768374872394904、21437238740213483874620、23412341234252346。注意其中第三个数，从9加1后，输出成0，而不是10

脚本：

declare    targetstr varchar2(2000);    strlength number;    position number;    maxposition number;    retrunstr varchar2(2000);    tempstr varchar2(2000);    endstr number;begin    targetstr := '1788987565327、768374872394903、21437238740213483874629、23412341234252345';    maxposition := 0;    select LENGTH(targetstr) into strlength  from dual;    for i in 1..strlength loop        select instr(str,'、',1,i) into position from （select targetstr as str from dual）;        --dbms_output.PUT_LINE(position);        if position > 0 then             if maxposition = 0 then                 select substr(str,0,instr(str,'、',1,1)-1) into retrunstr from （select targetstr as str from dual）;                select TO_NUMBER(substr(restr,-1)) into endstr from （select retrunstr as restr from dual）;                if endstr = 3 or endstr = 5 or endstr = 7 then                    endstr := endstr + 1;                elsif endstr = 9 then                    endstr := 0;                end if;                select substr(str,0,instr(str,'、',1,1)-2)||TO_CHAR(endstr) into retrunstr from （select targetstr as str from dual）;            elsif maxposition < position then                select substr(str,instr(str,'、',1,i-1)+1,instr(str,'、',1,i)-instr(str,'、',1,i-1)-1) into tempstr from （select targetstr as str from dual）;                select TO_NUMBER(substr(restr,-1)) into endstr from （select tempstr as restr from dual）;                if endstr = 3 or endstr = 5 or endstr = 7 then                    endstr := endstr + 1;                elsif endstr = 9 then                    endstr := 0;                end if;                select substr(str,1,length(str)-1) ||TO_CHAR(endstr) into tempstr from （select tempstr as str from dual）;                retrunstr := retrunstr || '、'|| tempstr;                         end if;            maxposition := position;        else            if maxposition > position then                --特别处理最后一段                tempstr := '';                select substr(str,maxposition-length(str)) into tempstr from （select targetstr as str from dual）;                select TO_NUMBER(substr(restr,-1)) into endstr from （select tempstr as restr from dual）;                if endstr = 3 or endstr = 5 or endstr = 7 then                    endstr := endstr + 1;                elsif endstr = 9 then                    endstr := 0;                end if;                select substr(str,1,length(str)-1) ||TO_CHAR(endstr) into tempstr from （select tempstr as str from dual）;                retrunstr := retrunstr || '、'|| tempstr;            end if;            exit;        end if;    end loop;    dbms_output.PUT_LINE(retrunstr);end;

运行结果如下：

原字符串：1788987565327、768374872394903、21437238740213483874629、23412341234252345

14:03:38 **** SCRIPT STARTED: 02-Apr-2015 14:03:38 ****
14:03:38 declare
14:03:38 targetstr varchar2(2000);
14:03:38 ...
14:03:39 PL/SQL block executed
1788987565328、768374872394904、21437238740213483874620、23412341234252346
14:03:39 **** SCRIPT ENDED 02-Apr-2015 14:03:39 ****
14:03:39 End Script Execution