简单的oracle 自定义函数

create or replace function get_businessId(businessId IN Varchar2) return varchar2 is

   Result Varchar2(50);

    v_businessId_length number;

BEGIN

    SELECT length(businessId) into v_businessId_length FROM dual;

    select substr(businessId,3,v_businessId_length) into Result from dual;

return(Result);

end get_businessId;