mysql通过substring_index和substring截取字符串

如mysql中有个列如下数值，怎么提出出其中ip地址

BGP-BeiJing-59.151.105.130-AD_read-YeZongKun

BGP-BeiJing-59.151.105.138_140_141-AD_LVS-YeZongKun

我提供sql语句如下：

select
SUBSTRING(substring_index(‘BGP-BeiJing-59.151.105.130-AD_read-YeZongKun’,'-’,3),(length(substring_index(‘BGP-BeiJing-59.151.105.130-AD_read-YeZongKun’,'-’,2))+2));


SUBSTRING

SUBSTRING(str,pos,len)

SUBSTRING(str FROM pos FOR len)

SUBSTRING(str,pos)

SUBSTRING(str FROM pos)

mysql> SELECT SUBSTRING(‘Quadratically’,5);

-> ‘ratically’

mysql> SELECT SUBSTRING(‘foobarbar’ FROM 4);

-> ‘barbar’

mysql> SELECT SUBSTRING(‘Quadratically’,5,6);

-> ‘ratica’

mysql> SELECT SUBSTRING(‘Sakila’, -3);

-> ‘ila’

mysql> SELECT SUBSTRING(‘Sakila’, -5, 3);

-> ‘aki’

mysql> SELECT SUBSTRING(‘Sakila’ FROM -4 FOR
2);

-> ‘ki’


substring_index

substring_index(str,delim,count)

mysql> SELECT SUBSTRING_INDEX(‘www.mysql.com’, ‘.’,
2);

-> ‘www.mysql’

mysql> SELECT SUBSTRING_INDEX(‘www.mysql.com’, ‘.’,
-2);

-> ‘mysql.com’