OUTER JOIN Meaning and
Definition
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An outer join is a type of join operation in relational databases that combines records from two or more tables based on a common attribute or key. It includes all the records from one table, called the "left" table, and matches them with corresponding records from another table, called the "right" table. The resulting table includes unmatched records from both tables as well.
The outer join operation can be performed in different ways: left outer join, right outer join, and full outer join. In a left outer join, all records from the left table are included, along with matching records from the right table. If there is no match, null values are included for the right table's attributes. Conversely, a right outer join preserves all records from the right table, including matching records from the left table and null values if there is no match.
A full outer join combines the results of both a left and right outer join, including all records from both tables. If a match exists between the tables, it includes the matching record; otherwise, null values are included for the unmatched attributes from either table.
Outer joins are used when there is a need to retrieve records from one table while maintaining all records from the other table, even if there is no match. This is particularly useful in scenarios where data might be missing in one of the tables or when performing analysis on data with potential incomplete relationships.
Common Misspellings for OUTER JOIN
- iuter join
- kuter join
- luter join
- puter join
- 0uter join
- 9uter join
- oyter join
- ohter join
- ojter join
- o8ter join
- o7ter join
- ourer join
- oufer join
- ouger join
- ouyer join
- ou6er join
- ou5er join
- outwr join
- outsr join
- outdr join
Etymology of OUTER JOIN
The term "outer join" originated in the field of relational databases. It combines the words "outer" and "join" to describe a type of operation that includes all the elements from two or more tables, while also including unmatched elements from one or both tables.
The term "join" refers to combining rows from different tables based on a common column or relationship. When two tables are joined, only the matching records are included in the result. However, there may be cases where you want to include unmatched records as well. That's where the concept of an "outer join" comes into play.
The word "outer" in "outer join" refers to the fact that unmatched records from one or both tables are included in the result, unlike an inner join that only includes matching records.
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