The other responders have answered your question, but just to help with your knowledge I'm going to add this, which I've used with a number of colleagues over the years.
A SQL join starts out (in the case of a two table join) by matching every record with the first table to every record from the second table. So, as @Astounding and @Reeza explain in the case of two tables with two records each, you start out with 2 x 2 or 4 result records.
There are actually cases where this is useful, but they are rare. So to get the desired results, you use other SQL clauses to "trim away" the result records you don't want.
The first is the left / right / inner join phrasing, accompanied by an "on" clause, where you're telling SQL that out of the enormous number of result records, ONLY keep the ones where there's a record in the left or the right table, or only the records where a field from the left table matches a field from the right table. This usually reduces the number of result records from a x b to the record count of a or b, or less depending on matching, which is usually more in line with what you want.
Once SQL has reduced the number of records based on your join logic, you can then reduce it even further using the "where" clause, which tells SQL to additionally only keep the records from the first part that match the conditions that you specify.
So, in conclusion, I always consider a SQL join as creating a massive result set, which I then trim away using the different language options.
Hope this helps, Tom
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