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Hyukjin Kwon updated SPARK-21513: --------------------------------- Labels: (was: Starter) > SQL to_json should support all column types > ------------------------------------------- > > Key: SPARK-21513 > URL: https://issues.apache.org/jira/browse/SPARK-21513 > Project: Spark > Issue Type: Improvement > Components: SQL > Affects Versions: 2.2.0 > Reporter: Aaron Davidson > > The built-in SQL UDF "to_json" currently supports serializing StructType > columns, as well as Arrays of StructType columns. If you attempt to use it on > a different type, for example a map, you get an error like this: > {code} > AnalysisException: cannot resolve 'structstojson(`tags`)' due to data type > mismatch: Input type map<string,string> must be a struct or array of > structs.;; > {code} > This limitation seems arbitrary; if I were to go through the effort of > enclosing my map in a struct, it would be serializable. Same thing with any > other non-struct type. > Therefore the desired improvement is to allow to_json to operate directly on > any column type. The associated code is > [here|https://github.com/apache/spark/blob/86174ea89b39a300caaba6baffac70f3dc702788/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/jsonExpressions.scala#L653]. -- 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