LEFT OUTER JOIN: produces a complete set of records from Table A, with the matching records (where available) in Table B. If there is no match, the right side will contain null.
RIGHT OUTER JOIN: produces a complete set of records from Table B, with the matching records (where available) in Table A. If there is no match, the left side will contain null.
FULL OUTER JOIN: produces the set of all records in Table A and Table B, with matching records from both sides where available. If there is no match, the missing side will contain null.
INNER JOIN: produces only the set of records that match in both Table A and Table B.
This is article can be found in its entirety here: https://www.geekphilip.com/2012/04/01/visual-explanation-of-sql-joins/
Thanks to Geek Phillip for making it easier to understand