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Liwei Lin 1dbb725dbe
[SPARK-16462][SPARK-16460][SPARK-15144][SQL] Make CSV cast null values properly 
## Problem

CSV in Spark 2.0.0:
-  does not read null values back correctly for certain data types such as `Boolean`, `TimestampType`, `DateType` -- this is a regression comparing to 1.6;
- does not read empty values (specified by `options.nullValue`) as `null`s for `StringType` -- this is compatible with 1.6 but leads to problems like SPARK-16903.

## What changes were proposed in this pull request?

This patch makes changes to read all empty values back as `null`s.

## How was this patch tested?

New test cases.

Author: Liwei Lin <lwlin7@gmail.com>

Closes #14118 from lw-lin/csv-cast-null.
2016-09-18 19:25:58 +01:00
..
catalyst [SPARK-17506][SQL] Improve the check double values equality rule. 2016-09-18 16:04:37 +01:00
core [SPARK-16462][SPARK-16460][SPARK-15144][SQL] Make CSV cast null values properly 2016-09-18 19:25:58 +01:00
hive [SPARK-17541][SQL] fix some DDL bugs about table management when same-name temp view exists 2016-09-18 21:15:35 +08:00
hive-thriftserver [SPARK-17190][SQL] Removal of HiveSharedState 2016-08-25 12:50:03 +08:00
README.md [SPARK-16557][SQL] Remove stale doc in sql/README.md 2016-07-14 19:24:42 -07:00

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 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 allows 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.