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Joins Algorithms


Joins Algorithms

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Alexandre Araujo
Alexandre Araujo
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Which is faster : Nested, Merge ou Hash Joins ?

Thanks.

Alexandre Araujo
Grant Fritchey
Grant Fritchey
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Yes.

Seriously though, each one is more efficient in a given situation. If both data sets are ordered, the Merge join is extremely efficient. If you have a smaller set of data in the inner loop, a nested loops join is extremely efficient. If your data is unordered and large, a hash join can work really well. It's completely situational which one works better in a given situation. That's why the optimizer has the choice. No one join will satisfy all situations.

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