Github user cloud-fan commented on a diff in the pull request:
https://github.com/apache/spark/pull/18540#discussion_r130035366
--- Diff:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/windowExpressions.scala
---
@@ -43,57 +42,65 @@ case class WindowSpecDefinition(
orderSpec: Seq[SortOrder],
frameSpecification: WindowFrame) extends Expression with WindowSpec
with Unevaluable {
- def validate: Option[String] = frameSpecification match {
- case UnspecifiedFrame =>
- Some("Found a UnspecifiedFrame. It should be converted to a
SpecifiedWindowFrame " +
- "during analysis. Please file a bug report.")
- case frame: SpecifiedWindowFrame => frame.validate.orElse {
- def checkValueBasedBoundaryForRangeFrame(): Option[String] = {
- if (orderSpec.length > 1) {
- // It is not allowed to have a value-based PRECEDING and
FOLLOWING
- // as the boundary of a Range Window Frame.
- Some("This Range Window Frame only accepts at most one ORDER BY
expression.")
- } else if (orderSpec.nonEmpty &&
!orderSpec.head.dataType.isInstanceOf[NumericType]) {
- Some("The data type of the expression in the ORDER BY clause
should be a numeric type.")
- } else {
- None
- }
- }
-
- (frame.frameType, frame.frameStart, frame.frameEnd) match {
- case (RangeFrame, vp: ValuePreceding, _) =>
checkValueBasedBoundaryForRangeFrame()
- case (RangeFrame, vf: ValueFollowing, _) =>
checkValueBasedBoundaryForRangeFrame()
- case (RangeFrame, _, vp: ValuePreceding) =>
checkValueBasedBoundaryForRangeFrame()
- case (RangeFrame, _, vf: ValueFollowing) =>
checkValueBasedBoundaryForRangeFrame()
- case (_, _, _) => None
- }
- }
- }
-
- override def children: Seq[Expression] = partitionSpec ++ orderSpec
+ override def children: Seq[Expression] = partitionSpec ++ orderSpec :+
frameSpecification
override lazy val resolved: Boolean =
childrenResolved && checkInputDataTypes().isSuccess &&
frameSpecification.isInstanceOf[SpecifiedWindowFrame]
override def nullable: Boolean = true
override def foldable: Boolean = false
- override def dataType: DataType = throw new UnsupportedOperationException
+ override def dataType: DataType = throw new
UnsupportedOperationException("dataType")
- override def sql: String = {
- val partition = if (partitionSpec.isEmpty) {
- ""
- } else {
- "PARTITION BY " + partitionSpec.map(_.sql).mkString(", ") + " "
+ override def checkInputDataTypes(): TypeCheckResult = {
+ frameSpecification match {
+ case UnspecifiedFrame =>
+ TypeCheckFailure(
+ "Cannot use an UnspecifiedFrame. This should have been converted
during analysis. " +
+ "Please file a bug report.")
+ case f: SpecifiedWindowFrame if f.frameType == RangeFrame &&
!f.isUnbounded &&
+ orderSpec.isEmpty =>
+ TypeCheckFailure(
+ "A range window frame cannot be used in an unordered window
specification.")
+ case f: SpecifiedWindowFrame if f.frameType == RangeFrame &&
f.isValueBound &&
+ orderSpec.size > 1 =>
+ TypeCheckFailure(
+ s"A range window frame with value boundaries cannot be used in a
window specification " +
+ s"with multiple order by expressions:
${orderSpec.mkString(",")}")
+ case f: SpecifiedWindowFrame if f.frameType == RangeFrame &&
f.isValueBound &&
+ !isValidFrameType(f.valueBoundary.head.dataType) =>
+ TypeCheckFailure(
+ s"The data type '${orderSpec.head.dataType}' used in the order
specification does " +
+ s"not match the data type '${f.valueBoundary.head.dataType}'
which is used in the " +
+ "range frame.")
+ case f: SpecifiedWindowFrame if !isValidFrameBoundary(f.lower,
f.upper) =>
+ TypeCheckFailure(s"The upper bound of the window frame is
'${f.upper.sql}', which is " +
+ s"smaller than the lower bound '${f.lower.sql}'.")
+ case _ => TypeCheckSuccess
}
+ }
- val order = if (orderSpec.isEmpty) {
- ""
- } else {
- "ORDER BY " + orderSpec.map(_.sql).mkString(", ") + " "
+ override def sql: String = {
+ def toSql(exprs: Seq[Expression], prefix: String): Seq[String] = {
+ Seq(exprs).filter(_.nonEmpty).map(_.map(_.sql).mkString(prefix, ",
", ""))
}
- s"($partition$order${frameSpecification.toString})"
+ val elements =
+ toSql(partitionSpec, "PARTITION BY ") ++
+ toSql(orderSpec, "ORDER BY ") ++
+ Seq(frameSpecification.sql)
+ elements.mkString("(", " ", ")")
+ }
+
+ private def isValidFrameType(ft: DataType): Boolean =
orderSpec.head.dataType == ft
+
+ private def isValidFrameBoundary(lower: Expression, upper: Expression):
Boolean = {
+ (lower, upper) match {
+ case (UnboundedFollowing, _) => false
+ case (_, UnboundedPreceding) => false
+ case (l: Expression, u: SpecialFrameBoundary) => !u.notFollows(l)
--- End diff --
do we need to consider `(u: SpecialFrameBoundary, l: Expression)`?
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