aea36aa977
This PR cherry picks https://github.com/apache/spark/pull/33235 to branch-3.2 to fix test failures introduced by https://github.com/apache/spark/pull/33284.
### What changes were proposed in this pull request?
This PR allows the `Project` node to host outer references in scalar subqueries when `decorrelateInnerQuery` is enabled. It is already supported by the new decorrelation framework and the `RewriteCorrelatedScalarSubquery` rule.
Note currently by default all correlated subqueries will be decorrelated, which is not necessarily the most optimal approach. Consider `SELECT (SELECT c1) FROM t`. This should be optimized as `SELECT c1 FROM t` instead of rewriting it as a left outer join. This will be done in a separate PR to optimize correlated scalar/lateral subqueries with OneRowRelation.
### Why are the changes needed?
To allow more types of correlated scalar subqueries.
### Does this PR introduce _any_ user-facing change?
Yes. This PR allows outer query column references in the SELECT cluase of a correlated scalar subquery. For example:
```sql
SELECT (SELECT c1) FROM t;
```
Before this change:
```
org.apache.spark.sql.AnalysisException: Expressions referencing the outer query are not supported
outside of WHERE/HAVING clauses
```
After this change:
```
+------------------+
|scalarsubquery(c1)|
+------------------+
|0 |
|1 |
+------------------+
```
### How was this patch tested?
Added unit tests and SQL tests.
(cherry picked from commit
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| .. | ||
| catalyst | ||
| core | ||
| hive | ||
| hive-thriftserver | ||
| create-docs.sh | ||
| gen-sql-api-docs.py | ||
| gen-sql-config-docs.py | ||
| gen-sql-functions-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.