I'm confused between LEFT JOIN and INNER JOIN - the differences and when it's appropriate to use one over the other. I tried to wrap my mind around it but it seems to me that INNER JOIN statements can always be rewritten as LEFT JOINs?
left joins will return all rows in the initial table regardless of whether or not they have a corresponding entry in the joined table. for rows that do not have a corresponding entry, null will be returned for all selected fields
inner joins will return only the rows in the initial that have a corresponding entry in the joined table.