spark-instrumented-optimizer/sql
Liang-Chi Hsieh 8b86326521 [SPARK-27551][SQL] Improve error message of mismatched types for CASE WHEN
## What changes were proposed in this pull request?

When there are mismatched types among cases or else values in case when expression, current error message is hard to read to figure out what and where the mismatch is.

This patch simply improves the error message for mismatched types for case when.

Before:
```scala
scala> spark.range(100).select(when('id === 1, array(struct('id * 123456789 + 123456789 as "x"))).otherwise(array(struct('id * 987654321 + 987654321 as
 "y"))))
org.apache.spark.sql.AnalysisException: cannot resolve 'CASE WHEN (`id` = CAST(1 AS BIGINT)) THEN array(named_struct('x', ((`id` * CAST(123456789 AS BI
GINT)) + CAST(123456789 AS BIGINT)))) ELSE array(named_struct('y', ((`id` * CAST(987654321 AS BIGINT)) + CAST(987654321 AS BIGINT)))) END' due to data
type mismatch: THEN and ELSE expressions should all be same type or coercible to a common type;;
```

After:
```scala
scala> spark.range(100).select(when('id === 1, array(struct('id * 123456789 + 123456789 as "x"))).otherwise(array(struct('id * 987654321 + 987654321 as
 "y"))))
org.apache.spark.sql.AnalysisException: cannot resolve 'CASE WHEN (`id` = CAST(1 AS BIGINT)) THEN array(named_struct('x', ((`id` * CAST(123456789 AS BI
GINT)) + CAST(123456789 AS BIGINT)))) ELSE array(named_struct('y', ((`id` * CAST(987654321 AS BIGINT)) + CAST(987654321 AS BIGINT)))) END' due to data
type mismatch: THEN and ELSE expressions should all be same type or coercible to a common type, got CASE WHEN ... THEN array<struct<x:bigint>> ELSE arr
ay<struct<y:bigint>> END;;
```

## How was this patch tested?

Added unit test.

Closes #24453 from viirya/SPARK-27551.

Authored-by: Liang-Chi Hsieh <viirya@gmail.com>
Signed-off-by: Dongjoon Hyun <dhyun@apple.com>
2019-04-25 08:47:19 -07:00
..
catalyst [SPARK-27551][SQL] Improve error message of mismatched types for CASE WHEN 2019-04-25 08:47:19 -07:00
core [SPARK-27551][SQL] Improve error message of mismatched types for CASE WHEN 2019-04-25 08:47:19 -07:00
hive [MINOR][TEST] switch from 2.4.1 to 2.4.2 in HiveExternalCatalogVersionsSuite 2019-04-25 10:26:40 +08:00
hive-thriftserver [SPARK-27404][CORE][SQL][STREAMING][YARN] Fix build warnings for 3.0: postfixOps edition 2019-04-11 13:43:44 -05:00
create-docs.sh [MINOR][DOCS] Minor doc fixes related with doc build and uses script dir in SQL doc gen script 2017-08-26 13:56:24 +09:00
gen-sql-markdown.py [SPARK-27328][SQL] Add 'deprecated' in ExpressionDescription for extended usage and SQL doc 2019-04-09 13:49:42 +08:00
mkdocs.yml [SPARK-21485][SQL][DOCS] Spark SQL documentation generation for built-in functions 2017-07-26 09:38:51 -07:00
README.md [MINOR][DOC] Fix some typos and grammar issues 2018-04-06 13:37:08 +08:00

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 an extension of SQLContext called HiveContext that allows 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.