“Outer join” is a type of join in databases that returns all records when there is a match in at least one of the tables. It is an extension of an inner join, working similarly, but requires an additional specification that does not have to be met in the query. Additionally, you can use LEFT, RIGHT, or FULL join types to specify whether you want to return records from only one table (LEFT or RIGHT) or all records from both tables (FULL). It is a useful tool for data analysis when you want to include all available information from both sources, regardless of whether the query conditions are met.
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