Join type for optimizing database queries
US10102248B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 27, 2015 |
| Grant date | Oct 16, 2018 |
| Priority date | — |
| Expiry date | Nov 12, 2036 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F16/24542
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A query complier analyzes a query to identify a correlated scalar subquery. The query complier transforms the query having the correlated scalar subquery into a query of AGGREGATION INNER/OUTER JOIN or MAX1ROW INNER/OUTER JOIN depending on a result type of the correlated scalar subquery. The AGGREGATION INNER/OUTER JOIN performs JOIN on the rows of the correlated scalar subquery with the rows of a main query and AGGREGATE on the joined rows and returns a result of the joined rows of the main query and aggregation value thereof. The MAX1ROW INNER/OUTER JOIN performs JOIN on the rows of the correlated scalar subquery with the rows of a main query, raises Error when the number of joined rows of the subquery is two or more and returns a result of the row of the main query and the joined row of the subquery.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.