Github user dilipbiswal commented on a diff in the pull request: https://github.com/apache/spark/pull/12222#discussion_r59791626 --- Diff: sql/core/src/main/scala/org/apache/spark/sql/execution/command/commands.scala --- @@ -423,6 +424,100 @@ case class ShowTablePropertiesCommand( } /** + * A command for users to list the column names for a table. This function creates a + * [[ShowColumnsCommand]] logical plan. + * + * The syntax of using this command in SQL is: + * {{{ + * SHOW COLUMNS (FROM | IN) table_identifier [(FROM | IN) database]; + * }}} + */ +case class ShowColumnsCommand(table: TableIdentifier) extends RunnableCommand { + // The result of SHOW COLUMNS has one column called 'result' + override val output: Seq[Attribute] = { + AttributeReference("result", StringType, nullable = false)() :: Nil + } + + override def run(sqlContext: SQLContext): Seq[Row] = { + val relation = sqlContext.sessionState.catalog.lookupRelation(table, None) + relation.schema.fields.map { field => + Row(field.name) + } --- End diff -- @andrewor14 Thanks Andrew. Let me re-base now :-)
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