Null aware anti-join
US7676450B2 · kind B2 · utility
12Cited by
21References
32Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Mar 8, 2007 |
| Grant date | Mar 9, 2010 |
| Priority date | — |
| Expiry date | Jan 30, 2028 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S707/99932
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Techniques for performing a “null-aware” anti-join operation are described. Unnesting using anti-join of NOT IN/ALL subquery uses null-aware anti-join operation, resulting in a rewritten query that, when computed, produces results consistent with the NULL semantics of NOT IN/ALL subquery. The semantics of the “null-aware” anti-join operation allow the query having the NOT IN/ALL subquery to be rewritten even though a no-NULL restriction requirement, for the operands of the anti-join condition in the query, may not be met.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.