Today was a day of frustration. Mostly conceptual frustration. Before we get to that though. I did learn some stuff…
I learned:
In SQLite one can ORDER BY category_name DESC to order the data by that category. One can also JOIN tables together. There are three types of joining: INNER JOIN, LEFT JOIN, and OUTER JOIN. INNER JOIN is the default JOIN which takes one similar category from two datasets and sets them equal to each other on a combined dataset. This will not show any values which do not overlap between the two data though, so it might not show all the information. The LEFT and OUTER joins are what I’m currently having trouble understanding…
I’m still confused on:
I sort of understand that these will fill in missing values with a null object, so it can be good for showing all the data, but I so far don’t quite understand the difference between these two. If outer join can connect the outside data, what’s the use in left join? Can’t one just specify which category? Why does it need to be one of the outside categories?
I know this is a relatively simple concept. I will spend more brain power looking into it tomorrow. For right now though, I just need to get to some other work.
Isaac Gazmararian 