Database Design 41 - Introduction to Joins 

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Ellie Worsley Hi Ellie, To be honest, some of these I have not heard of. I'd love to hear more about the ones I don't know, though. Because I wouldn't mind maybe making videos over them. An equijoin is based on an equality. So for the examples I gave in these videos I had an ON table.column_id = table.column_id. That makes it an equijoin! I have a video over outer joins. In fact, I have a good amount on inner and outer joins and doing them across 2 or 3 tables. I will hopefully be making a video on Union within the next few weeks (probably not in time for when you need it haha). A natural join works the same way as an inner join or outer join or whatever, the only difference is that it will try to figure out what columns to join automatically by itself. So rather than saying user_id = user_id for example, it will figure that out automatically because it's the only column that is in both tables. Don't think that each join is its own thing. An inner join can be a natural join, or an inner join can be an equijoin. natural join and equijoins are a different thing than outer and inner joins. natural and equijoins refer to how you join data while inner and outer refers to what data to return... if that makes sense. Probably not though because I'm awful at explaining things through comments. So just check out the rest of this series :)

CalebTheVideoMaker2 Hey Caleb, I see the EQUijoin now, EQUals... Lol, thank you! With my course we study Relational Algebra and Relational Calculs like I mentioned before, this means that we study the Relational Algebra Operations, one of them being the Cartesian Product. The Cartesian Product defines a relation that is the concatenation of every tuple of realtion R with every tuple of relation S, e.g. relation R, has column a and column b and Relation S has column 1 column 2 and column 3. Therefore to carry out the cartesian product you would times the number of columns by each other; 2 x 3 would give our new relation 6 tuples: a1 a2 a3 b1 b2 b3 Therefore because we do this we use the Cartesian Product in our joins meaning we only use two relations (probably for the simpler lol). I have looked at your join videos and they have actually been a big help so thank you! And thank you for getting back to me! :) Take Care, Ellie.

Sorry I meant analyticalizationalysis!

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Syntactical and analyzation are words. But 100%, analization is not a word. And analyticalizationalysis, well... Please get on it Merriam-Webster!

ya u did