Github user chenghao-intel commented on a diff in the pull request:
https://github.com/apache/spark/pull/16476#discussion_r95282270
--- Diff:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/conditionalExpressions.scala
---
@@ -340,3 +344,102 @@ object CaseKeyWhen {
CaseWhen(cases, elseValue)
}
}
+
+/**
+ * A function that returns the index of expr in (expr1, expr2, ...) list
or 0 if not found.
+ * It takes at least 2 parameters, and all parameters should be subtype of
AtomicType or NullType.
+ * It's also acceptable to give parameters of different types.
+ * If the search string is NULL, the return value is 0 because NULL fails
equality comparison with any value.
+ * When the paramters have different types, comparing will be done based
on type firstly,
+ * for example, ''999'' won't be considered equal with 999, no implicit
cast will be done here.
+ */
+@ExpressionDescription(
+ usage = "_FUNC_(expr, expr1, expr2, ...) - Returns the index of expr in
the expr1, expr2, ... or 0 if not found.",
+ extended = """
+ Examples:
+ > SELECT _FUNC_(10, 9, 3, 10, 4);
+ 3
+ > SELECT _FUNC_('a', 'b', 'c', 'd', 'a');
+ 4
+ > SELECT _FUNC_('999', 'a', 999, 9.99, '999');
+ 4
+ """)
+case class Field(children: Seq[Expression]) extends Expression {
+
+ /** Even if expr is not found in (expr1, expr2, ...) list, the value
will be 0, not null */
+ override def nullable: Boolean = false
+ override def foldable: Boolean = children.forall(_.foldable)
+
+ private lazy val ordering =
TypeUtils.getInterpretedOrdering(children(0).dataType)
+
+ private val dataTypeMatchIndex: Seq[Int] = children.tail.zip(Stream from
1).filter(
+ _._1.dataType == children.head.dataType).map(_._2)
+
+ override def checkInputDataTypes(): TypeCheckResult = {
+ if (children.length <= 1) {
+ TypeCheckResult.TypeCheckFailure(s"FIELD requires at least 2
arguments")
+ } else if (!children.forall(
+ e => e.dataType.isInstanceOf[AtomicType] ||
e.dataType.isInstanceOf[NullType])) {
+ TypeCheckResult.TypeCheckFailure(s"FIELD requires all arguments to
be of AtomicType")
+ } else
+ TypeCheckResult.TypeCheckSuccess
+ }
+
+ override def dataType: DataType = IntegerType
+ override def eval(input: InternalRow): Any = {
+ val target = children.head.eval(input)
+ val targetDataType = children.head.dataType
--- End diff --
Unused code.
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