What is Joins in Database explain it with write example?

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Amrita Bhattacharjee · Answer

A join in a database refers to the combination of rows from two or more tables based on a related column between them. The result shows one table with columns from the joined tables.

The types of joins in SQL includes:

Inner Join: It is used to return only the rows whereas there exists a match in two tables.
Left Outer Join: It is used to return all of the rows from the left table and the rows which are in match from the right table.
Right Outer Join : It is used to return all of the rows from the right table and the rows which are matching from the left table.
Full Outer Join: It is used to return all of the rows from both the tables, including the unmatched rows as well.

As an example,If we have have two tables including "Customers" and "Orders", with the following data:

Customers table:

ID	Name
1	John
2	Sarah
3	Mike

Orders table:

ID	OrderID	CustomerID
1	1001	1
2	1002	2
3	1003	1

If we join these two tables on the "CustomerID" column then we will get the following result:

Result of INNER JOIN:

ID	Name	OrderID	CustomerID
1	John	1001	1
1	John	1003	1
2	Sarah	1002	2

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What is Joins in Database explain it with write example?

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