Improved Unnesting Algorithms for Join Aggregate SQL Queries

Summary: Presents a modified Kim unnesting algorithm for join-aggregate SQL queries that avoids the COUNT bug while retaining efficiency. Precomputed aggregates and top-down join/outer-join evaluation reduce Cartesian products and broaden applicability. (summarized by gpt-5.6-luna on Jul 24 2026)

Paper ID: h2ac9d5d73c8dfc0d
Venue: VLDB
Year: 1992
Pagerank: 0.00012468327
Overall Rank: 1,015 | 93.20%
DOI: -

Incoming Non-self Citations Over Time

Authors

1. M. Muralikrishna (Digital Equipment Corporation)

BibTeX Citation

@article{muralikrishna_vldb92,
        title = {{Improved Unnesting Algorithms for Join Aggregate SQL Queries}},
        author = {Muralikrishna, M.},
        journal = {PVLDB},
        series = {{VLDB} '92},
        year = {1992}
}

Incoming Citations (Sorted by Pagerank)

Showing 20 of 20 citing papers.

Rank	Citing Paper	Year	Venue	Pagerank
73	Including Group-By in Query Optimization	1994	VLDB	0.00037420958
259	An Overview of Query Optimization in Relational Systems	1998	PODS	0.00022881075
1,122	Query Optimization by Predicate Move-Around	1994	VLDB	0.00011915958
1,380	Experiences Building the Open OODB Query Optimizer	1993	SIGMOD	0.00010835212
1,381	Execution Strategies for SQL Subqueries	2007	SIGMOD	0.00010832197
1,888	WeTune: Automatic Discovery and Verification of Query Rewrite Rules	2022	SIGMOD	9.4148912e-05
2,122	Enhanced Subquery Optimizations in Oracle	2009	VLDB	8.9938885e-05
2,971	Proving Query Equivalence Using Linear Integer Arithmetic	2023	SIGMOD	7.7851336e-05
3,144	Solving the Join Ordering Problem via Mixed Integer Linear Programming	2017	SIGMOD	7.5846375e-05
3,158	GenRewrite: Query Rewriting via Large Language Models	2026	SIGMOD	7.5676704e-05
3,702	Implementation of Magic-sets in a Relational Database System	1994	SIGMOD	7.0617354e-05
3,857	EROC: A Toolkit for Building NEATO Query Optimizers	1996	VLDB	6.9553827e-05
4,197	Rule Languages and Internal Algebras for Rule-Based Optimizers	1996	SIGMOD	6.7307148e-05
4,694	Efficient Evaluation of XQuery over Streaming Data	2005	VLDB	6.4490159e-05
6,064	Query Unnesting in Object-Oriented Databases	1998	SIGMOD	5.8826375e-05
7,371	SQL Query Optimization: Reordering for a General Class of Queries	1996	SIGMOD	5.5257045e-05
7,927	A Practical Approach to Groupjoin and Nested Aggregates	2021	VLDB	5.4082473e-05
7,941	SlabCity: Whole-Query Optimization using Program Synthesis	2023	VLDB	5.4056478e-05
9,687	Window Function Expression: Let the Self-join Enter	2024	VLDB	5.1258854e-05
13,065	A Nested Relational Approach to Processing SQL Subqueries	2005	SIGMOD	4.9605343e-05

Outgoing Citations (Sorted by Pagerank)

Showing 5 of 5 cited papers.

Citations counted here include only citations to other VLDB/SIGMOD/CIDR/PODS papers in this database.

Rank	Cited Paper	Year	Venue	Pagerank
99	Of Nests and Trees: A Unified Approach to Processing Queries That Contain Nested Subqueries, Aggregates, and Quantifiers	1987	VLDB	0.00034024478
133	Optimization of Nested SQL Queries Revisited	1987	SIGMOD	0.0003015194
334	Implementation Of A Structured English Query Language	1975	SIGMOD	0.00020692791
1,063	Query Graphs, Implementing Trees, and Freely-Reorderable Outerjoins	1990	SIGMOD	0.00012198695
2,874	Optimization and Dataflow Algorithms for Nested Tree Queries	1989	VLDB	7.898744e-05

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9	13,065	A Nested Relational Approach to Processing SQL Subqueries	2005	SIGMOD
10	2,874	Optimization and Dataflow Algorithms for Nested Tree Queries	1989	VLDB