Uncorrelated subquery optimization method and apparatus, and storage medium
US11269878B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jul 25, 2019 |
| Grant date | Mar 8, 2022 |
| Priority date | — |
| Expiry date | Oct 3, 2039 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F16/24549
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
The embodiments of this application provide an uncorrelated subquery optimization method and apparatus, and a storage medium. The method includes determining whether there is an uncorrelated subquery statement in a target clause in a database query statement. In response to the determination that there is the uncorrelated subquery statement in the target clause in the database query statement, the method includes obtaining an estimated number of rows of an execution result set corresponding to the target clause; and determining whether the estimated number of rows is less than a preset threshold. In response to the determination that the estimated number of rows is less than a preset threshold, the method includes executing the uncorrelated subquery statement, and rewriting the target clause according to an execution result set of the uncorrelated subquery statement, to eliminate the uncorrelated subquery statement.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.