71022d7130
### What changes were proposed in this pull request?
At the moment we do not have any function to compute length of JSON array directly.
I propose a `json_array_length` function which will return the length of the outermost JSON array.
- This function will return length of the outermost JSON array, if JSON array is valid.
```
scala> spark.sql("select json_array_length('[1,2,3,[33,44],{\"key\":[2,3,4]}]')").show
+--------------------------------------------------+
|json_array_length([1,2,3,[33,44],{"key":[2,3,4]}])|
+--------------------------------------------------+
| 5|
+--------------------------------------------------+
scala> spark.sql("select json_array_length('[[1],[2,3]]')").show
+------------------------------+
|json_array_length([[1],[2,3]])|
+------------------------------+
| 2|
+------------------------------+
```
- In case of any other valid JSON string, invalid JSON string or null array or `NULL` input , `NULL` will be returned.
```
scala> spark.sql("select json_array_length('')").show
+-------------------+
|json_array_length()|
+-------------------+
| null|
+-------------------+
```
### Why are the changes needed?
- As mentioned in JIRA, this function is supported by presto, postgreSQL, redshift, SQLite, MySQL, MariaDB, IBM DB2.
- for better user experience and ease of use.
```
Performance Result for Json array - [1, 2, 3, 4]
Intel(R) Core(TM) i7-9750H CPU 2.60GHz
JSON functions: Best Time(ms) Avg Time(ms) Stdev(ms) Rate(M/s) Per Row(ns) Relative
------------------------------------------------------------------------------------------------------------------------
json_array_length 7728 7762 53 1.3 772.8 1.0X
size+from_json 12739 12895 199 0.8 1273.9 0.6X
```
### Does this PR introduce any user-facing change?
Yes, now users can get length of a json array by using `json_array_length`.
### How was this patch tested?
Added UT.
Closes #27759 from iRakson/jsonArrayLength.
Authored-by: iRakson <raksonrakesh@gmail.com>
Signed-off-by: Dongjoon Hyun <dongjoon@apache.org>
|
||
|---|---|---|
| .. | ||
| 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.