621e37e2ab
### What changes were proposed in this pull request? Spark SQL support single comments and bracketed comments now. This PR will support nested bracketed comments. There are some mainstream database support the syntax. **PostgreSQL:** https://www.postgresql.org/docs/11/sql-syntax-lexical.html#SQL-SYNTAX-COMMENTS **Vertica:** https://www.vertica.com/docs/9.2.x/HTML/Content/Authoring/SQLReferenceManual/LanguageElements/Expressions/Comments.htm?zoom_highlight=comments Note: Because Spark SQL not exists UT for single comments and bracketed comments, so I add some UT for them. ### Why are the changes needed? nested bracketed comments is ANSI standard. ### Does this PR introduce any user-facing change? No ### How was this patch tested? New UT Closes #27495 from beliefer/nested-brancket-comments. Authored-by: beliefer <beliefer@163.com> Signed-off-by: Gengliang Wang <gengliang.wang@databricks.com> |
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| .. | ||
| catalyst | ||
| core | ||
| hive | ||
| hive-thriftserver | ||
| create-docs.sh | ||
| gen-sql-api-docs.py | ||
| gen-sql-config-docs.py | ||
| mkdocs.yml | ||
| README.md | ||
Spark SQL
This module provides support for executing relational queries expressed in either SQL or the DataFrame/Dataset API.
Spark SQL is broken up into four subprojects:
- Catalyst (sql/catalyst) - An implementation-agnostic framework for manipulating trees of relational operators and expressions.
- Execution (sql/core) - A query planner / execution engine for translating Catalyst's logical query plans into Spark RDDs. This component also includes a new public interface, SQLContext, that allows users to execute SQL or LINQ statements against existing RDDs and Parquet files.
- Hive Support (sql/hive) - Includes extensions that allow users to write queries using a subset of HiveQL and access data from a Hive Metastore using Hive SerDes. There are also wrappers that allow users to run queries that include Hive UDFs, UDAFs, and UDTFs.
- HiveServer and CLI support (sql/hive-thriftserver) - Includes support for the SQL CLI (bin/spark-sql) and a HiveServer2 (for JDBC/ODBC) compatible server.
Running ./sql/create-docs.sh generates SQL documentation for built-in functions under sql/site, and SQL configuration documentation that gets included as part of configuration.md in the main docs directory.