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Gideon P commented on SPARK-47353: ---------------------------------- [~uros-db] I will claim this one > Mode (all collations) > --------------------- > > Key: SPARK-47353 > URL: https://issues.apache.org/jira/browse/SPARK-47353 > Project: Spark > Issue Type: Sub-task > Components: SQL > Affects Versions: 4.0.0 > Reporter: Uroš Bojanić > Priority: Major > > Enable collation support for the *Mode* expression in Spark. First confirm > what is the expected behaviour for this expression when given collated > strings, then move on to the implementation that would enable handling > strings of all collation types. Implement the corresponding unit tests and > E2E SQL tests to reflect how this function should be used with collation in > SparkSQL, and feel free to use your chosen Spark SQL Editor to experiment > with the existing functions to learn more about how they work. In addition, > look into the possible use-cases and implementation of similar functions > within other other open-source DBMS, such as > [PostgreSQL|https://www.postgresql.org/docs/]. > > The goal for this Jira ticket is to implement the *Mode* expression so it > supports all collation types currently supported in Spark. To understand what > changes were introduced in order to enable full collation support for other > existing functions in Spark, take a look at the Spark PRs and Jira tickets > for completed tasks in this parent (for example: Contains, StartsWith, > EndsWith). > Examples: > With UTF8_BINARY collation, the query > SELECT mode(col) FROM VALUES (‘a’), (‘a’), (‘a’), (‘B’), (‘B’), (‘b’), (‘b’) > AS tab(col); > should return 'a'. > With UTF8_BINARY_LCASE collation, the query > SELECT mode(col) FROM VALUES (‘a’), (‘a’), (‘a’), (‘B’), (‘B’), (‘b’), (‘b’) > AS tab(col); > should return either 'B' or 'b'. > > Read more about ICU [Collation Concepts|http://example.com/] and > [Collator|http://example.com/] class. Also, refer to the Unicode Technical > Standard for > [collation|https://www.unicode.org/reports/tr35/tr35-collation.html#Collation_Type_Fallback]. -- This message was sent by Atlassian Jira (v8.20.10#820010) --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@spark.apache.org For additional commands, e-mail: issues-h...@spark.apache.org