can someone explain to me exactally what join does? in dont understand exactly how to use it and i dont understand the diffrences between inner join, left join, and right join (and are there more?). i am creating a search engine that has to be quite advanced and i talked to a friend who showed me some good ways of doing it. heres what i have planned but im not real sure i understand whats going on.
table query_from -
(1) join mdl_cv_personal_info as personal_info //i see it creates a nick name for it called personal_info
(2) join mdl_cv_personal_info_lang as personal_info_lang
//thats it for the beginning of the 1st table
table query_select -
title++++++|++++++++field_name++++++++|+query_from_id+|
first_name | personal_info.first_name | 1
last_name | personal_info.last_name | 1
information| personal_info_lang.info | 2
//the first_name is queryed from the join in the 1st table etc...
table query_where -
//really not clear on how to do this but maybe somthing like
(1) first_name (=, !=, <, >, like...pick one of these somehow) personal_info.first_name
as you can probebly tell i am a bit lost and i cant read the mysql documentation cause that makes even less sence to me. any help would be nice. thanks