如何将字符串mysql db分成两个字段？

i have a leads table that has a field named referrer..which has data like this

refferer 
yahoo:fine dining
google:cash register
google:sale systems

google:or sale
http://www.somesite.com/
google:software

This data is the php $_SERVER['HTTP_REFERER'] but this is all in one field ...is there an easy way to split this up in two fields seperated by the : so the final result should be two fields ...Also the referrer field maybe blank as well

refferer                     keyword
yahoo                        fine dining
google                       cash register

google                       sale systems
google                       or sale
http://www.somesite.com/
google                       software

I really just need an update statement that will seperate the keyword and insert into the keyword field

i looked at mysql string functions and noticed SUBSTRING_INDEX but not sure if that would be the best tool for this task

You can use

SELECT SUBSTRING_INDEX(referrer, ':', -1) as keyword,SUBSTRING_INDEX(referrer, ':', 1) as referrer FROM table;