On conjunctive queries containing inequalities
Journal of the ACM (JACM)
The complexity of querying indefinite data about linearly ordered domains
PODS '92 Proceedings of the eleventh ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Minimizing restricted-fanout queries
Discrete Applied Mathematics - Special issue on combinatorial problems in databases
Optimization of real conjunctive queries
PODS '93 Proceedings of the twelfth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Equivalence, query-reachability and satisfiability in Datalog extensions
PODS '93 Proceedings of the twelfth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Containment of conjunctive queries: beyond relations as sets
ACM Transactions on Database Systems (TODS)
Semantic query optimization in Datalog programs (extended abstract)
PODS '95 Proceedings of the fourteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Deciding equivalences among aggregate queries
PODS '98 Proceedings of the seventeenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Rewriting aggregate queries using views
PODS '99 Proceedings of the eighteenth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Efficient optimization of a class of relational expressions
ACM Transactions on Database Systems (TODS)
Equivalences Among Relational Expressions with the Union and Difference Operators
Journal of the ACM (JACM)
Conjunctive query containment revisited
Theoretical Computer Science - Special issue on the 6th International Conference on Database Theory—ICDT '97
Static analysis in datalog extensions
Journal of the ACM (JACM)
Principles of Database and Knowledge-Base Systems: Volume II: The New Technologies
Principles of Database and Knowledge-Base Systems: Volume II: The New Technologies
Functional and inclusion dependencies a graph theoretic approach
PODS '84 Proceedings of the 3rd ACM SIGACT-SIGMOD symposium on Principles of database systems
Inclusion dependencies and the universal instance
PODS '83 Proceedings of the 2nd ACM SIGACT-SIGMOD symposium on Principles of database systems
Testing containment of conjunctive queries under functional and inclusion dependencies
PODS '82 Proceedings of the 1st ACM SIGACT-SIGMOD symposium on Principles of database systems
Implication and Referential Constraints: A New Formal Reasoning
IEEE Transactions on Knowledge and Data Engineering
Decidable Containment of Recursive Queries
ICDT '03 Proceedings of the 9th International Conference on Database Theory
Containment of Aggregate Queries
ICDT '03 Proceedings of the 9th International Conference on Database Theory
Optimal implementation of conjunctive queries in relational data bases
STOC '77 Proceedings of the ninth annual ACM symposium on Theory of computing
Equivalences among aggregate queries with negation
ACM Transactions on Computational Logic (TOCL)
The containment problem for Real conjunctive queries with inequalities
Proceedings of the twenty-fifth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Containment of conjunctive queries on annotated relations
Proceedings of the 12th International Conference on Database Theory
Spatial aggregation: Data model and implementation
Information Systems
Equivalence of queries that are sensitive to multiplicities
The VLDB Journal — The International Journal on Very Large Data Bases
Equivalence of nested queries with mixed semantics
Proceedings of the twenty-eighth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Equivalence of SQL queries in presence of embedded dependencies
Proceedings of the twenty-eighth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Proceedings of the thirtieth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Equivalence and minimization of conjunctive queries under combined semantics
Proceedings of the 15th International Conference on Database Theory
ACM Transactions on Database Systems (TODS)
| Hi-index | 0.00 |
The query equivalence problem has been studied extensively for set-semantics and, more recently, for bag-set semantics. However, SQL queries often combine set and bag-set semantics. For example, an SQL query that returns a multiset of elements may call a subquery or view that returns a set of elements. As another example, in SQL one can compute a multiset-union of queries, each of which returns a set of answers. This paper presents combined semantics, which formally models query evaluation combining set and bag-set semantics. The equivalence problem for queries evaluated under combined semantics is studied. A sufficient condition for equivalence is presented. For several important common classes of queries necessary and sufficient conditions for equivalence are presented.