Topic : Joins

Explain some examples of join methods.


Answer :

Join methods are of mainly 3 types.

Merge Join -
- Sorting both the tables using join key and then merge the rows which are sorted.
Nested loop join -
- It gets a result set after applying filter conditions based on the outer table.
- Then it joins the inner table with the respective result set.
Hash join -
- It uses hash algorithm first on smaller table and then on the other table to produce joined columns. After that matching rows are returned.

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