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  2. Merge (SQL) - Wikipedia

    en.wikipedia.org/wiki/Merge_(SQL)

    A right join is employed over the Target (the INTO table) and the Source (the USING table / view / sub-query)--where Target is the left table and Source is the right one. The four possible combinations yield these rules:

  3. Join (SQL) - Wikipedia

    en.wikipedia.org/wiki/Join_(SQL)

    Join order: Because it joins functions commutatively and associatively, the order in which the system joins tables does not change the final result set of the query. However, join-order could have an enormous impact on the cost of the join operation, so choosing the best join order becomes very important. Join method: Given two tables and a ...

  4. diff3 - Wikipedia

    en.wikipedia.org/wiki/Diff3

    diff3 has several methods to handle overlaps and conflicts. It can omit overlaps or conflicts, or select only overlaps, or mark conflicts with special <<<<< and >>>>> lines. diff3 can output the merge results as an ed script that can be applied to the first file to yield the merged output. However, directly generating the merged output bypasses ...

  5. Relational algebra - Wikipedia

    en.wikipedia.org/wiki/Relational_algebra

    The right outer join ( ) behaves almost identically to the left outer join, but the roles of the tables are switched. The right outer join of relations R and S is written as R S. [e] The result of the right outer join is the set of all combinations of tuples in R and S that are equal on their common attribute names, in addition to tuples in S ...

  6. Sort-merge join - Wikipedia

    en.wikipedia.org/wiki/Sort-merge_join

    The sort-merge join (also known as merge join) is a join algorithm and is used in the implementation of a relational database management system. The basic problem of a join algorithm is to find, for each distinct value of the join attribute, the set of tuples in each relation which display that value. The key idea of the sort-merge algorithm is ...

  7. Comparison of file comparison tools - Wikipedia

    en.wikipedia.org/wiki/Comparison_of_file...

    Merge Structured comparison [b] Manual compare alignment Image compare Beyond Compare: Yes Yes Yes Yes Yes (Files and Folders) Yes (Pro only) Yes Yes Compare++: Yes Yes Yes Yes Yes (C/C++,C#,Java,Javascript,CSS3) diff: No Yes partly No No No diff3: No No Yes (non-optional) Eclipse (compare) Yes No (only ancestor) Yes No Ediff: Yes Yes Yes Yes ...

  8. Merge (version control) - Wikipedia

    en.wikipedia.org/wiki/Merge_(version_control)

    Manual merging is also required when automatic merging runs into a change conflict; for instance, very few automatic merge tools can merge two changes to the same line of code (say, one that changes a function name, and another that adds a comment). In these cases, revision control systems resort to the user to specify the intended merge result.

  9. Correlated subquery - Wikipedia

    en.wikipedia.org/wiki/Correlated_subquery

    In a SQL database query, a correlated subquery (also known as a synchronized subquery) is a subquery (a query nested inside another query) that uses values from the outer query. This can have major impact on performance because the correlated subquery might get recomputed every time for each row of the outer query is processed.