oracle字符串从后面（右边)查找

--oracle字符串从后面查找 by yanleigis Email:landgis@126.com
function lastindex(str in varchar2, findstr in varchar2) return integer is
i integer;
num integer;
subln integer;
begin
num := length(str);
subln := length(findstr);
if subln > num then
return - 1;
end if;
i := num - subln + 1;
while i > 0 loop
if substr(str, i, subln) = findstr then
return i;
end if;
i := I - 1;
end loop;
return - 1;
end;