commit | b2be7e1dacaefd93c6aaccc1192694610e4d2457 | [log] [tgz] |
---|---|---|
author | Paul Jackson <pauljackson123@verizon.net> | Wed Nov 01 15:42:23 2023 -0400 |
committer | Julian Hyde <jhyde@apache.org> | Fri Jan 12 17:26:38 2024 -0800 |
tree | d94413b80ea18e7727522583c106f623339ba431 | |
parent | ad2a4e6af21ab27952c7152e670783559e49735e [diff] |
[CALCITE-6044] RelMetadataQuery should regard single-row relational expressions as unique A single-row relation can result from a LIMIT 1 or an aggregation without GROUP BY. Every column in one of these relations should be unique by virtue of having a max row count of 1. When joining with a single-row relation on a key field, the join result should no longer require that key field for uniqueness. For example, suppose the emp table had a composite key (empno,hiredate). If we join on hiredate=max(hiredate) then empno alone should be a unique column. Close apache/calcite#3495
Apache Calcite is a dynamic data management framework.
It contains many of the pieces that comprise a typical database management system but omits the storage primitives. It provides an industry standard SQL parser and validator, a customisable optimizer with pluggable rules and cost functions, logical and physical algebraic operators, various transformation algorithms from SQL to algebra (and the opposite), and many adapters for executing SQL queries over Cassandra, Druid, Elasticsearch, MongoDB, Kafka, and others, with minimal configuration.
For more details, see the home page.
The project uses JIRA for issue tracking. For further information, please see the JIRA accounts guide.