在oracle805中创建function的问题?

[webwing]

以下语句为什么会出错?
CREATE or Replace function F_GETMIN(
first NUMBER,
second NUMBER)
RETURN NUMBER IS
NUMBER rtn;
BEGIN
if first<=second then
rtn: = first;
else
rtn: = second;
end if;
return rtn;
END F_GETMIN;

[mashansj]

CREATE or Replace function F_GETMIN(
first NUMBER,
second NUMBER)
RETURN NUMBER IS
rtn NUMBER;
BEGIN
if first<=second then
rtn:=first;
else
rtn:=second;
end if;
return rtn;
END F_GETMIN;
/

[carion]

变量定义错了