beliefer commented on a change in pull request #30479:
URL: https://github.com/apache/spark/pull/30479#discussion_r539132890
##########
File path:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/stringExpressions.scala
##########
@@ -2082,6 +2083,65 @@ case class UnBase64(child: Expression)
}
}
+object Decode {
+ def createExpr(params: Seq[Expression]): Expression = {
+ params.length match {
+ case 0 | 1 =>
+ throw new AnalysisException("Invalid number of arguments for function
decode. " +
+ s"Expected: 2; Found: ${params.length}")
+ case 2 => StringDecode(params.head, params.last)
+ case _ =>
+ val input = params.head
+ val other = params.tail
+ val itr = other.iterator
+ var default: Expression = Literal.create(null, StringType)
+ val branches = ArrayBuffer.empty[(Expression, Expression)]
+ while (itr.hasNext) {
+ val search = itr.next
+ if (itr.hasNext) {
+ val condition = EqualTo(input, search)
+ branches += ((condition, itr.next))
+ } else {
+ default = search
+ }
+ }
+ CaseWhen(branches.seq, default)
+ }
+ }
+}
+
+// scalastyle:off line.size.limit
+@ExpressionDescription(
+ usage = """
+ |_FUNC_(bin, charset) - Decodes the first argument using the
second argument character set.
+ |
+ |_FUNC_(expr, search, result [, search, result ] ... [, default])
- Decode compares expr
+ | to each search value one by one. If expr is equal to a search,
returns the corresponding result.
+ | If no match is found, then Oracle returns default. If default
is omitted, returns null.
+ """,
+ examples = """
+ Examples:
+ > SELECT _FUNC_(encode('abc', 'utf-8'), 'utf-8');
+ abc
+ > SELECT _FUNC_(2, 1, 'Southlake', 2, 'San Francisco', 3, 'New Jersey',
4, 'Seattle', 'Non domestic');
+ San Francisco
+ > SELECT _FUNC_(6, 1, 'Southlake', 2, 'San Francisco', 3, 'New Jersey',
4, 'Seattle', 'Non domestic');
+ Non domestic
+ > SELECT _FUNC_(6, 1, 'Southlake', 2, 'San Francisco', 3, 'New Jersey',
4, 'Seattle');
+ NULL
+ """,
+ since = "3.1.0")
Review comment:
OK
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