Github user yijieshen commented on a diff in the pull request:
https://github.com/apache/spark/pull/6874#discussion_r33116959
--- Diff:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/complexTypeCreator.scala
---
@@ -78,3 +77,50 @@ case class CreateStruct(children: Seq[Expression])
extends Expression {
InternalRow(children.map(_.eval(input)): _*)
}
}
+
+/**
+ * Creates a struct with the given field names and values
+ *
+ * @param children Seq(name1, val1, name2, val2, ...)
+ */
+case class CreateNamedStruct(children: Seq[Expression]) extends Expression
{
+
+ private lazy val (nameExprs, valExprs) =
+ children.grouped(2).map { case Seq(name, value) => (name, value)
}.toList.unzip
+
+ private lazy val names =
nameExprs.map(_.eval(EmptyRow).asInstanceOf[UTF8String].toString)
+
+ override lazy val dataType: StructType = {
+ val fields = names.zip(valExprs).map { case (name, valExpr) =>
+ StructField(name, valExpr.dataType, valExpr.nullable, Metadata.empty)
+ }
+ StructType(fields)
+ }
+
+ override def foldable: Boolean = children.forall(_.foldable)
+
+ override def nullable: Boolean = false
+
+ override def checkInputDataTypes(): TypeCheckResult = {
+ if (children.size % 2 != 0) {
+ TypeCheckResult.TypeCheckFailure("CreateNamedStruct expects an even
number of arguments.")
+ } else {
+ val invalidNames = nameExprs.filter { case name =>
+ (name.find {
+ case _: Attribute | _: BoundReference => true;
+ case _ => false
+ } != None) || (name.dataType != StringType)
+ }
--- End diff --
I tried to find a doc on this but there didn't exist one. But Hive allows
the above Query:
```
"""SELECT named_struct(
lower("AA"), "10",
repeat(lower("AA"), 3), "11",
lower(repeat("AA", 3)), "12",
printf("Bb%d", 12), "13",
repeat(printf("s%d", 14), 2), "14") FROM src LIMIT 1"""
```
in which case expressions on constant is also regarded as valid `name`
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at [email protected] or file a JIRA ticket
with INFRA.
---
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
