Github user cloud-fan commented on a diff in the pull request:
https://github.com/apache/spark/pull/13976#discussion_r69388270
--- Diff:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/generators.scala
---
@@ -195,3 +195,38 @@ case class Explode(child: Expression) extends
ExplodeBase(child, position = fals
extended = "> SELECT _FUNC_(array(10,20));\n 0\t10\n 1\t20")
// scalastyle:on line.size.limit
case class PosExplode(child: Expression) extends ExplodeBase(child,
position = true)
+
+/**
+ * Explodes an array of structs into a table.
+ */
+@ExpressionDescription(
+ usage = "_FUNC_(a) - Explodes an array of structs into a table.",
+ extended = "> SELECT _FUNC_(array(struct(1, 'a'), struct(2, 'b')));\n
[1,a]\n [2,b]")
+case class Inline(child: Expression) extends UnaryExpression with
Generator with CodegenFallback {
+
+ override def children: Seq[Expression] = child :: Nil
+
+ override def checkInputDataTypes(): TypeCheckResult = child.dataType
match {
+ case ArrayType(et, _) if et.isInstanceOf[StructType] =>
+ TypeCheckResult.TypeCheckSuccess
+ case _ =>
+ TypeCheckResult.TypeCheckFailure(
+ s"input to function $prettyName should be array of struct type,
not ${child.dataType}")
+ }
+
+ override def elementSchema: StructType = child.dataType match {
+ case ArrayType(et : StructType, _) => et
+ }
+
+ private lazy val numFields = elementSchema.fields.length
+
+ override def eval(input: InternalRow): TraversableOnce[InternalRow] = {
+ val inputArray = child.eval(input).asInstanceOf[ArrayData]
+ if (inputArray == null) {
+ Nil
+ } else {
+ for (i <- 0 until inputArray.numElements())
+ yield inputArray.getStruct(i, numFields)
--- End diff --
I'm not sure how is the performance of `for-yield`, maybe it's safe to
create an array manually and use while loop here?
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