From 06cc6f313c21bddbae25fb4ee6cdd62e8cd8bd78 Mon Sep 17 00:00:00 2001
From: robot-clickhouse <robot-clickhouse@users.noreply.github.com>
Date: Wed, 16 Oct 2024 11:08:37 +0000
Subject: [PATCH] Backport #68848 to 24.8: Fix empty tuple in array

---
 src/Functions/array/arrayElement.cpp                           | 3 +++
 tests/queries/0_stateless/03229_empty_tuple_in_array.reference | 1 +
 tests/queries/0_stateless/03229_empty_tuple_in_array.sql       | 1 +
 3 files changed, 5 insertions(+)
 create mode 100644 tests/queries/0_stateless/03229_empty_tuple_in_array.reference
 create mode 100644 tests/queries/0_stateless/03229_empty_tuple_in_array.sql

diff --git a/src/Functions/array/arrayElement.cpp b/src/Functions/array/arrayElement.cpp
index 81f3f97979b..d0b2b49cc1c 100644
--- a/src/Functions/array/arrayElement.cpp
+++ b/src/Functions/array/arrayElement.cpp
@@ -1598,6 +1598,9 @@ ColumnPtr FunctionArrayElement::executeTuple(const ColumnsWithTypeAndName & argu
     const auto & tuple_columns = col_nested->getColumns();
     size_t tuple_size = tuple_columns.size();
 
+    if (tuple_size == 0)
+        return ColumnTuple::create(input_rows_count);
+
     const DataTypes & tuple_types = typeid_cast<const DataTypeTuple &>(
         *typeid_cast<const DataTypeArray &>(*arguments[0].type).getNestedType()).getElements();
 
diff --git a/tests/queries/0_stateless/03229_empty_tuple_in_array.reference b/tests/queries/0_stateless/03229_empty_tuple_in_array.reference
new file mode 100644
index 00000000000..6a452c185a8
--- /dev/null
+++ b/tests/queries/0_stateless/03229_empty_tuple_in_array.reference
@@ -0,0 +1 @@
+()
diff --git a/tests/queries/0_stateless/03229_empty_tuple_in_array.sql b/tests/queries/0_stateless/03229_empty_tuple_in_array.sql
new file mode 100644
index 00000000000..09ba3595a5a
--- /dev/null
+++ b/tests/queries/0_stateless/03229_empty_tuple_in_array.sql
@@ -0,0 +1 @@
+select [()][0];