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closed with the note: duplicate

Can we say inner and self join are same ?

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natural join :The result of the natural join is the set of all combinations of tuples in R and S that are equal on their common attribute names    Source :https://en.wikipedia.org/wiki/Relational_algebra#.CE.B8-join_and_equijoin

inner join :'inner join' is opposed to 'outer join' and determines how to join two sets when there is no matching value.   source :https://stackoverflow.com/questions/5471063/is-inner-join-the-same-as-equi-join

equi join:'equi-join' means joining tables using the equality operator or equivalent.

theta join :θ is a binary relational operator in the set {<, ≤, =, >, ≥}, v is a value constant, and R and S are relations. The result of this operation consists of all combinations of tuples in R and S that satisfy θ. The result of the θ-join is defined only if the headers of S and R are disjoint, that is, do not contain a common attribute.

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