[Oracle|오라클] 한글 초성 검색 함수

직원명을 초성으로 검색할수 있도록 요청이 들어와서
급하게 만들었다.

직원수가 아주많은곳에서는 where절에 사용하면 안됨...

예) fn_korinitialkeyword('홍길동')
return : ㅎㄱㄷ

select *
from 테이블
where fn_korinitialkeyword(직원명컬럼) like '%ㅎㄱㄷ%'

function fn_korinitialkeyword( str in varchar2) return varchar2 is    returnStr varchar2(100);     cnt number := 0;     tmpStr varchar2(10); begin        if str is null then       return '';       end if;              cnt := length(str);        for i in 1 .. cnt       loop         tmpStr := substr(str,i,1);                        returnStr := returnStr ||       case when tmpStr < 'ㄱ' then substr(tmpStr, 1, 1)             when ascii('ㄱ') <= ascii(tmpStr) and ascii(tmpStr) <= ascii('ㅎ') then chr(ascii(tmpStr))             when tmpStr < '나' then 'ㄱ'             when tmpStr < '다' then 'ㄴ'             when tmpStr < '라' then 'ㄷ'             when tmpStr < '마' then 'ㄹ'             when tmpStr < '바' then 'ㅁ'             when tmpStr < '사' then 'ㅂ'             when tmpStr < '아' then 'ㅅ'             when tmpStr < '자' then 'ㅇ'             when tmpStr < '차' then 'ㅈ'             when tmpStr < '카' then 'ㅊ'             when tmpStr < '타' then 'ㅋ'             when tmpStr < '파' then 'ㅌ'             when tmpStr < '하' then 'ㅍ'             else 'ㅎ'       end;        end loop;             return returnStr; end;