Query processing techniques in the summary-table-by-example database query language
ACM Transactions on Database Systems (TODS)
Optimization and dataflow algorithms for nested tree queries
VLDB '89 Proceedings of the 15th international conference on Very large data bases
The functional data model and the data languages DAPLEX
ACM Transactions on Database Systems (TODS)
Processing queries with quantifiers a horticultural approach
PODS '83 Proceedings of the 2nd ACM SIGACT-SIGMOD symposium on Principles of database systems
Extending the Algebraic Framework of Query Processing to Handle Outerjoins
VLDB '84 Proceedings of the 10th International Conference on Very Large Data Bases
Supporting Flat Relations by a Nested Relational Kernel
VLDB '87 Proceedings of the 13th International Conference on Very Large Data Bases
VLDB '87 Proceedings of the 13th International Conference on Very Large Data Bases
Join processing in relational databases
ACM Computing Surveys (CSUR)
Extensible/rule based query rewrite optimization in Starburst
SIGMOD '92 Proceedings of the 1992 ACM SIGMOD international conference on Management of data
SIGMOD '94 Proceedings of the 1994 ACM SIGMOD international conference on Management of data
Hypergraph based reorderings of outer join queries with complex predicates
SIGMOD '95 Proceedings of the 1995 ACM SIGMOD international conference on Management of data
SQL query optimization: reordering for a general class of queries
SIGMOD '96 Proceedings of the 1996 ACM SIGMOD international conference on Management of data
Outerjoin simplification and reordering for query optimization
ACM Transactions on Database Systems (TODS)
An overview of query optimization in relational systems
PODS '98 Proceedings of the seventeenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Optimizing Queries with Universal Quantification in Object-Oriented and Object-Relational Databases
VLDB '97 Proceedings of the 23rd International Conference on Very Large Data Bases
Improved Unnesting Algorithms for Join Aggregate SQL Queries
VLDB '92 Proceedings of the 18th International Conference on Very Large Data Bases
No regression algorithm for the enumeration of projections in SQL queries with joins and outer joins
CASCON '95 Proceedings of the 1995 conference of the Centre for Advanced Studies on Collaborative research
Nested Queries and Quantifiers in an Ordered Context
ICDE '04 Proceedings of the 20th International Conference on Data Engineering
Canonical abstraction for outerjoin optimization
SIGMOD '04 Proceedings of the 2004 ACM SIGMOD international conference on Management of data
Full disjunctions: polynomial-delay iterators in action
VLDB '06 Proceedings of the 32nd international conference on Very large data bases
Cost-based query transformation in Oracle
VLDB '06 Proceedings of the 32nd international conference on Very large data bases
Strategies for query unnesting in XML databases
ACM Transactions on Database Systems (TODS)
Dynamic programming strikes back
Proceedings of the 2008 ACM SIGMOD international conference on Management of data
Speculative execution plan for multiple query execution systems
Annales UMCS, Informatica
On the correct and complete enumeration of the core search space
Proceedings of the 2013 ACM SIGMOD International Conference on Management of Data
Query optimization over crowdsourced data
Proceedings of the VLDB Endowment
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We determine when a join/outerjoin query can be expressed unambiguously as a query graph, without an explicit specification of the order of evaluation. To do so, we first characterize the set of expression trees that implement a given join/outerjoin query graph, and investigate the existence of transformations among the various trees. Our main theorem is that a join/outerjoin query is freely reorderable if the query graph derived from it falls within a particular class, every tree that “implements” such a graph evaluates to the same result.The result has applications to language design and query optimization. Languages that generate queries within such a class do not require the user to indicate priority among join operations, and hence may present a simplified syntax. And it is unnecessary to add extensive analyses to a conventional query optimizer in order to generate legal reorderings for a freely-reorderable language.