[
https://issues.apache.org/jira/browse/SPARK-21110?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16061398#comment-16061398
]
Michael Armbrust commented on SPARK-21110:
------------------------------------------
It seems if you can call {{min}} and {{max}} on structs you should be able to
use comparison operations as well.
> Structs should be usable in inequality filters
> ----------------------------------------------
>
> Key: SPARK-21110
> URL: https://issues.apache.org/jira/browse/SPARK-21110
> Project: Spark
> Issue Type: Improvement
> Components: SQL
> Affects Versions: 2.1.1
> Reporter: Nicholas Chammas
> Priority: Minor
>
> It seems like a missing feature that you can't compare structs in a filter on
> a DataFrame.
> Here's a simple demonstration of a) where this would be useful and b) how
> it's different from simply comparing each of the components of the structs.
> {code}
> import pyspark
> from pyspark.sql.functions import col, struct, concat
> spark = pyspark.sql.SparkSession.builder.getOrCreate()
> df = spark.createDataFrame(
> [
> ('Boston', 'Bob'),
> ('Boston', 'Nick'),
> ('San Francisco', 'Bob'),
> ('San Francisco', 'Nick'),
> ],
> ['city', 'person']
> )
> pairs = (
> df.select(
> struct('city', 'person').alias('p1')
> )
> .crossJoin(
> df.select(
> struct('city', 'person').alias('p2')
> )
> )
> )
> print("Everything")
> pairs.show()
> print("Comparing parts separately (doesn't give me what I want)")
> (pairs
> .where(col('p1.city') < col('p2.city'))
> .where(col('p1.person') < col('p2.person'))
> .show())
> print("Comparing parts together with concat (gives me what I want but is
> hacky)")
> (pairs
> .where(concat('p1.city', 'p1.person') < concat('p2.city', 'p2.person'))
> .show())
> print("Comparing parts together with struct (my desired solution but
> currently yields an error)")
> (pairs
> .where(col('p1') < col('p2'))
> .show())
> {code}
> The last query yields the following error in Spark 2.1.1:
> {code}
> org.apache.spark.sql.AnalysisException: cannot resolve '(`p1` < `p2`)' due to
> data type mismatch: '(`p1` < `p2`)' requires (boolean or tinyint or smallint
> or int or bigint or float or double or decimal or timestamp or date or string
> or binary) type, not struct<city:string,person:string>;;
> 'Filter (p1#5 < p2#8)
> +- Join Cross
> :- Project [named_struct(city, city#0, person, person#1) AS p1#5]
> : +- LogicalRDD [city#0, person#1]
> +- Project [named_struct(city, city#0, person, person#1) AS p2#8]
> +- LogicalRDD [city#0, person#1]
> {code}
--
This message was sent by Atlassian JIRA
(v6.4.14#64029)
---------------------------------------------------------------------
To unsubscribe, e-mail: issues-unsubscr...@spark.apache.org
For additional commands, e-mail: issues-h...@spark.apache.org
