Hisoka-X commented on code in PR #42398:
URL: https://github.com/apache/spark/pull/42398#discussion_r1368586674
##########
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/aggregate/collect.scala:
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@@ -245,3 +249,98 @@ case class CollectTopK(
override def withNewInputAggBufferOffset(newInputAggBufferOffset: Int):
CollectTopK =
copy(inputAggBufferOffset = newInputAggBufferOffset)
}
+
+@ExpressionDescription(
+ usage = "_FUNC_(expr) - Returns the concatenated input values," +
+ " separated by the delimiter string.",
+ examples = """
+ Examples:
+ > SELECT _FUNC_(col) FROM VALUES ('a'), ('b'), ('c') AS tab(col);
+ a,b,c
+ > SELECT _FUNC_(col) FROM VALUES (NULL), ('a'), ('b') AS tab(col);
+ a,b
+ > SELECT _FUNC_(col) FROM VALUES ('a'), ('a') AS tab(col);
+ a,a
+ > SELECT _FUNC_(DISTINCT col) FROM VALUES ('a'), ('a'), ('b') AS
tab(col);
+ a,b
+ > SELECT _FUNC_(col, '|') FROM VALUES ('a'), ('b') AS tab(col);
+ a|b
+ > SELECT _FUNC_(col) FROM VALUES (NULL), (NULL) AS tab(col);
+ ""
+ """,
+ group = "agg_funcs",
+ since = "4.0.0")
+case class ListAgg(
+ child: Expression,
+ delimiter: Expression = Literal.create(",", StringType),
+ orderExpression: Expression,
+ reverse: Boolean = false,
+ mutableAggBufferOffset: Int = 0,
+ inputAggBufferOffset: Int = 0) extends Collect[mutable.ArrayBuffer[Any]]
Review Comment:
I had tried with that. It seem like can't change bufferElementType in
`CollectList` but `ListAgg` want to save two expression result. And this way
will rewrite some method in `CollectList` like `eval`, `update`, so I didn't
find the value of inheriting `CollectList`, it seems that it is only same with
generic classes? Please point out my mistake. Thanks.
These are code.
<details>
<summary>ListAgg</summary>
```scala
case class ListAgg(
child: Expression,
delimiter: Expression = Literal.create(",", StringType),
orderExpression: Expression,
reverse: Boolean = false,
mutableAggBufferOffset: Int = 0,
inputAggBufferOffset: Int = 0) extends
TypedImperativeAggregate[mutable.ArrayBuffer[Any]]
with BinaryLike[Expression] {
def this(child: Expression) =
this(child, Literal.create(",", StringType), child, false, 0, 0)
def this(child: Expression, delimiter: Expression) =
this(child, delimiter, child, false, 0, 0)
private lazy val collect = CollectList(child, mutableAggBufferOffset,
inputAggBufferOffset)
// override protected def convertToBufferElement(value: Any): Any =
InternalRow.copyValue(value)
override def defaultResult: Option[Literal] = Option(Literal.create("",
StringType))
// TODO seem like hard to change bufferElementType in collect
// override protected lazy val bufferElementType: DataType = {
// StructType(Seq(
// StructField("value", child.dataType),
// StructField("sortOrder", orderExpression.dataType)))
// }
override def merge(buffer: ArrayBuffer[Any], input: ArrayBuffer[Any]):
ArrayBuffer[Any] = {
collect.merge(buffer, input)
}
override def serialize(buffer: ArrayBuffer[Any]): Array[Byte] = {
collect.serialize(buffer)
}
override def deserialize(storageFormat: Array[Byte]): ArrayBuffer[Any] = {
collect.deserialize(storageFormat)
}
override def eval(buffer: mutable.ArrayBuffer[Any]): Any = {
if (buffer.nonEmpty) {
val ordering = PhysicalDataType.ordering(orderExpression.dataType)
val sorted = if (reverse) {
buffer.asInstanceOf[mutable.ArrayBuffer[InternalRow]].toSeq.sortBy(_.get(1,
orderExpression.dataType))(ordering.asInstanceOf[Ordering[AnyRef]].reverse).map(_.get(0,
child.dataType))
} else {
buffer.asInstanceOf[mutable.ArrayBuffer[InternalRow]].toSeq.sortBy(_.get(1,
orderExpression.dataType))(ordering.asInstanceOf[Ordering[AnyRef]]).map(_.get(0,
child.dataType))
}
UTF8String.fromString(sorted.map(_.toString)
.mkString(delimiter.eval().asInstanceOf[UTF8String].toString))
} else {
UTF8String.fromString("")
}
}
override def update(buffer: ArrayBuffer[Any], input: InternalRow):
ArrayBuffer[Any] = {
val value = child.eval(input)
if (value != null) {
buffer += InternalRow.apply(collect.convertToBufferElement(value),
collect.convertToBufferElement(orderExpression.eval(input)))
}
buffer
}
override def createAggregationBuffer(): mutable.ArrayBuffer[Any] =
mutable.ArrayBuffer.empty
override def withNewMutableAggBufferOffset(
newMutableAggBufferOffset: Int) : ImperativeAggregate =
copy(mutableAggBufferOffset = newMutableAggBufferOffset)
override def withNewInputAggBufferOffset(newInputAggBufferOffset: Int):
ImperativeAggregate =
copy(inputAggBufferOffset = newInputAggBufferOffset)
override def nullable: Boolean = false
override def dataType: DataType = StringType
override def left: Expression = child
override def right: Expression = orderExpression
override protected def withNewChildrenInternal(
newLeft: Expression,
newRight: Expression): Expression = {
copy(child = newLeft, orderExpression = newRight)
}
}
```
</details>
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