Group by substring

问题:

I have a field with text like "/site/index?sid=18&sub=321333&tid=site.net&ukey=1234543254".

How can I group it by part of string( 'sid' url param e.g.)?
And params may be in a different order.(sid on the end of line and etc.)

回答1:

Take a look at the MySQL string functions:

http://dev.mysql.com/doc/refman/5.0/en/string-functions.html

Especially this looks helpful:

http://dev.mysql.com/doc/refman/5.0/en/string-functions.html#function_substring-index

UPDATE

This is exactly what you asked for:

SELECT SUBSTRING_INDEX(SUBSTRING_INDEX("/site/index?sid=18&sub=321333&tid=site.net&ukey=1234543254", 'sid=', -1), '&', 1) AS this_will_be_grouped

and use this_will_be_grouped in the GROUP BY clause of your query