Thread: Self-Join and Cross Join

Forum : Hibernate Framework FAQ?s and Interview Questions   22 Days ago
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Self-Join and Cross Join

| Quote Date : 3 May, 2019    Views:166    

What is Join and Why it is required? Explain different type of joins? What is the difference between Self-Join and Cross Join?

tags: java


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Re: Self-Join and Cross Join

Reply Date : 10 May, 2019

Joins are used to retrieve the data from the multiples tables.
In oracle we can also retrieve the data from multiple tables without using joins. i.e whenever we are specifying no of tables
within the from clause of the select statement then oracle server internally uses cross join but cross join is implemented based on the cartision product. That's why this joins returns more no. of rows.
If we want to compare two different column values within the same table then we must use self join.joining a table itself is called
self join.but here these columns must belongs to same datatype.

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