Add json array tail function

extension/json/CMakeLists.txt

@@ -31,6 +31,7 @@ set(JSON_EXTENSION_FILES
     json_functions/json_serialize_sql.cpp
     json_functions/read_json.cpp
     json_functions/read_json_objects.cpp
+    json_functions/json_array_tail.cpp
     json_functions/json_array_append.cpp
     ${YYJSON_OBJECT_FILES})
 

extension/json/include/json_functions.hpp

@@ -102,7 +102,8 @@ class JSONFunctions {
 	static ScalarFunctionSet GetSerializeSqlFunction();
 	static ScalarFunctionSet GetDeserializeSqlFunction();
 
-    static ScalarFunctionSet GetArrayAppendFunction();
+	static ScalarFunctionSet GetArrayTailFunction();
+	static ScalarFunctionSet GetArrayAppendFunction();
 	static PragmaFunctionSet GetExecuteJsonSerializedSqlPragmaFunction();
 
 	template <class FUNCTION_INFO>

extension/json/json_config.py

@@ -32,6 +32,7 @@
         'extension/json/json_serializer.cpp',
         'extension/json/json_deserializer.cpp',
         'extension/json/serialize_json.cpp',
+        'extension/json/json_array_tail.cpp',
         'extension/json/json_array_append.cpp',
     ]
 ]

extension/json/json_functions/json_array_tail.cpp

@@ -0,0 +1,33 @@
+#include "json_executors.hpp"
+
+namespace duckdb {
+
+static void ArrayTailFunction(DataChunk &args, ExpressionState &state, Vector &result) {
+	JSONExecutors::UnaryMutExecute(args, state, result,
+	                               [](yyjson_mut_val *arr, yyjson_mut_doc *doc, yyjson_alc *alc, Vector &result) {
+		                               if (!yyjson_mut_is_arr(arr)) {
+			                               throw InvalidInputException("JSON input not an JSON Array");
+		                               }
+
+		                               if (yyjson_mut_arr_size(arr) == 0) {
+			                               return yyjson_mut_arr(doc);
+		                               }
+
+		                               yyjson_mut_arr_remove_first(arr);
+		                               return arr;
+	                               });
+}
+
+static void GetArrayTailFunctionInternal(ScalarFunctionSet &set, const LogicalType &input_type) {
+	set.AddFunction(ScalarFunction("json_array_tail", {input_type}, JSONCommon::JSONType(), ArrayTailFunction, nullptr,
+	                               nullptr, nullptr, JSONFunctionLocalState::Init));
+}
+
+ScalarFunctionSet JSONFunctions::GetArrayTailFunction() {
+	ScalarFunctionSet set("json_array_tail");
+	GetArrayTailFunctionInternal(set, LogicalType::VARCHAR);
+	GetArrayTailFunctionInternal(set, JSONCommon::JSONType());
+	return set;
+}
+
+} // namespace duckdb

test/sql/json/scalar/test_json_array_tail.test

@@ -0,0 +1,47 @@
+# name: test/sql/json/scalar/test_json_array_tail.test
+# description: Checks whether a given JSON Array's tail is correct
+# group: [scalar]
+
+require json
+
+statement ok
+PRAGMA enable_verification
+
+# list with varchar to json
+statement ok
+create table test (j json)
+
+statement ok
+insert into test values('[]'), ('[42]'), ('["a", 42, true]')
+
+query I
+SELECT json_array_tail(j) FROM test
+----
+[]
+[]
+[42,true]
+
+statement error
+SELECT json_array_tail('')
+---
+Error: Invalid Input Error: Malformed JSON at byte 0 of input: input length is 0.  Input:
+
+statement error
+SELECT json_array_tail('{}')
+---
+Error: Invalid Input Error: JSON input not a JSON Array
+
+statement error
+SELECT json_array_tail('true')
+---
+Error: Invalid Input Error: JSON input not a JSON Array
+
+statement error
+SELECT json_array_tail('"Hello"')
+---
+Error: Invalid Input Error: JSON input not a JSON Array
+
+statement error
+SELECT json_array_tail('42')
+---
+Error: Invalid Input Error: JSON input not a JSON Array