UnresolvedWindowExpression Unevaluable Expression — WindowExpression With Unresolved Window Specification Reference

UnresolvedWindowExpression is an unevaluable expression that represents…​FIXME

Note
 An unevaluable expression cannot be evaluated to produce a value (neither in interpreted nor code-generated expression evaluations) and has to be resolved (replaced) to some other expressions or logical operators at analysis or optimization phases or they fail analysis.

UnresolvedWindowExpression is created when:

  • FIXME

UnresolvedWindowExpression is created to represent a child expression and WindowSpecReference (with an identifier for the window reference) when AstBuilder parses a function evaluated in a windowed context with a WindowSpecReference.

UnresolvedWindowExpression is resolved to a WindowExpression when Analyzer resolves UnresolvedWindowExpressions.

import spark.sessionState.sqlParser

scala> sqlParser.parseExpression("foo() OVER windowSpecRef")
res1: org.apache.spark.sql.catalyst.expressions.Expression = unresolvedwindowexpression('foo(), WindowSpecReference(windowSpecRef))
Table 1. UnresolvedWindowExpression’s Properties
Name Description

dataType

Reports a UnresolvedException

foldable

Reports a UnresolvedException

nullable

Reports a UnresolvedException

resolved

Disabled (i.e. false)

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