Differances between INNER JOIN and OUTER JOIN

I was curious as to the situations when you would use INNER JOIN over OUTER JOIN and OUTER JOIN over INNER JOIN and what data LEFT JOIN would pull? I am currently using INNER JOIN to join 2 tables for relational reasons but cant really figure out OUTER JOIN so thought I should ask.

Thanks

which was written by guys who likely know what they're doing but can't splain it clearly to save their lifes

a lot of people like this visual representation -- http://mxtutorial.com/2011/05/visual-sql-joins/

of course, i have a fond attachment to my explanation in this old thread on sitepoint, which eventually made it into my book -- http://www.sitepoint.com/forums/sho...42&postcount=18

So the full outer join is saying everything that doesn't match from table a and table b as in your example?

oh, that would only be the case if we did a where clause for NULL?

yeah, sort of

see, the diagrams are also hard to grasp at first, aren't they

also, notice there is no diagram for cross join

Yes i noticed that and didn't even know that cross joining existed, I am curious as to what you would use that for?

you would use a cross join to generate all possible combinations of pairs of values

just remember that, and you will recognize the opportunity when it arises -- which isn't often, admittedly, but the cross join can be very useful

That is great information, thanks a lot.