Concepts
Joins
Left join
All rows from the left table and the matching rows from the right table. If a row in the left table does not have a match in the right table, the result will contain null values for all columns of the right table.
Right join
All rows from the right table and the matching rows from the left table. If a row in the right table does not have a match in the left table, the result will contain null values for all columns of the left table.
Inner join
Matching rows of both tables. If a row in either table does not have a match in the other table, that row will not be included in the result set.
Outer join (left or right)
All rows from one table and the matching rows from another table. If a row in one table does not have a match in the other table, the result will contain null values for all columns of the other table.
Full outer join
All rows from both tables, whether there is a match or not. Any unmatched rows from either table will be represented by null values in the result set.