On this post I will go over the most common command you will see in queries and probably the most you will be using as a beginner.
JOIN - will remove rows that do not have anything in common with the other table(s)
LEFT JOIN - will identify the data from right table that you are looking for to combine with your table located to the left (see below image) whether or not there is a match
ALIAS - a name you would like to give your table
ON - this is a filter condition similar to the "WHERE" clause
Reiteration:
JOIN - I only want items to show where tablea.name = tableb.name exists
LEFT JOIN - I want the data from tableb whether or not there is a match.
I am of course showing an over simplified explanation. If you wish to learn more, this site my help: https://www.w3schools.com/sql/sql_join.asp
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