% different ways of connecting tables with LEFT JOIN. USING( fieldname )
% connects the table being joined, with the table listed right before it,
% using the same fieldname in both. The ON syntax allows you to use
% differently named fields, and/or a different table.
I still don't get what a left or right or outer or inner join is...
When looking up values in a second table, LEFT JOIN has two properties
that make it my choice:
o It lets me specify exactly how the tables are linked together.
o It returns results for the first table even if there are no entries
in the second table. For example, if one of my classes did not yet have
a room assigned, the rest of the data will still be returned.
I've read the mysql docs for the syntax and some examples, but this is
a place where I'll need to go to outside tutorials. Do you know of
any (on the web) which will give me the background?
http://www.devshed.com/Server_Side/MySQL/Join/page5.html
http://www.google.com/search?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=sql+join+tutorial