SQL LEFT JOIN command detailed _ database other

Let's give a plain explanation.
Example Table A
Aid Adate
1 A1
2 A2
3 A3
Table B
Bid Bdate
1 B1
2 B2
4 B4
Two table a,b connected, to remove fields with the same ID
SELECT * from a INNER join B on a.aid = B.bid This is the only matching data to be fetched.
At this point, the removal is:
1 A1 B1
2 A2 B2
So the left join means:
SELECT * from a LEFT join B on a.aid = B.bid
First remove all the data from table A and then add the data that matches the A,b
At this point, the removal is:
1 A1 B1
2 A2 B2
3 A3 NULL characters
There is also the right join
It means to first remove all the data from table B and then add the data that matches the a,b.
At this point, the removal is:
1 A1 B1
2 A2 B2
4 NULL character B4

Left JOIN or left OUTER join.
The result set of a left outer join consists of all the rows of the left table specified in the OUTER clause, not just the rows that the join columns match. If a row in the left table does not have a matching row in the right table, all picklist columns in the right table in the associated result set row are null values.