mysql的字符串操作,该如何处理

mysql的字符串操作
有个字符串'34173cb38f07f89d'，想把它每4位用空格隔开，请问用哪个函数？
想要的效果为：3417 3cb3 8f07 f89d

[解决办法]
期待高人给出好办法。
下面用了三个函数，你也可以只用 substring 函数来做。

SQL code

mysql> select @str := "34173cb38f07f89d";+----------------------------+| @str := "34173cb38f07f89d" |+----------------------------+| 34173cb38f07f89d            |+----------------------------+1 row in setmysql> select @str;+------------------+| @str             |+------------------+| 34173cb38f07f89d |+------------------+1 row in setmysql> select @str, concat(left(@str, 4), " ", substring(@str, 4, 4), " ", substring(@str, 8, 4), " ", right(@str, 4)) as "new_str";+------------------+---------------------+| @str             | new_str             |+------------------+---------------------+| 34173cb38f07f89d | 3417 73cb 38f0 f89d |+--+--+1 row in set