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new 05bb56913e feat: Add `array_max` function support (#14470)
05bb56913e is described below
commit 05bb56913ecaeed981c8913cca030af482e6c39b
Author: Eren Avsarogullari <[email protected]>
AuthorDate: Fri Mar 7 02:26:18 2025 -0800
feat: Add `array_max` function support (#14470)
* Issue-14469 - feat: Add array_max function
* Address review comments
* Address review comments II
* Address review comments III
---
datafusion/functions-aggregate/src/min_max.rs | 2 +-
datafusion/functions-nested/src/lib.rs | 2 +
datafusion/functions-nested/src/max.rs | 137 +++++++++++++++++++++++++
datafusion/sqllogictest/test_files/array.slt | 87 ++++++++++++++++
docs/source/user-guide/sql/scalar_functions.md | 33 ++++++
5 files changed, 260 insertions(+), 1 deletion(-)
diff --git a/datafusion/functions-aggregate/src/min_max.rs
b/datafusion/functions-aggregate/src/min_max.rs
index 90fb46883d..83356e2f9f 100644
--- a/datafusion/functions-aggregate/src/min_max.rs
+++ b/datafusion/functions-aggregate/src/min_max.rs
@@ -573,7 +573,7 @@ fn min_batch(values: &ArrayRef) -> Result<ScalarValue> {
}
/// dynamically-typed max(array) -> ScalarValue
-fn max_batch(values: &ArrayRef) -> Result<ScalarValue> {
+pub fn max_batch(values: &ArrayRef) -> Result<ScalarValue> {
Ok(match values.data_type() {
DataType::Utf8 => {
typed_min_max_batch_string!(values, StringArray, Utf8, max_string)
diff --git a/datafusion/functions-nested/src/lib.rs
b/datafusion/functions-nested/src/lib.rs
index 41ebb4366c..446cd58865 100644
--- a/datafusion/functions-nested/src/lib.rs
+++ b/datafusion/functions-nested/src/lib.rs
@@ -52,6 +52,7 @@ pub mod map;
pub mod map_extract;
pub mod map_keys;
pub mod map_values;
+pub mod max;
pub mod planner;
pub mod position;
pub mod range;
@@ -144,6 +145,7 @@ pub fn all_default_nested_functions() ->
Vec<Arc<ScalarUDF>> {
length::array_length_udf(),
distance::array_distance_udf(),
flatten::flatten_udf(),
+ max::array_max_udf(),
sort::array_sort_udf(),
repeat::array_repeat_udf(),
resize::array_resize_udf(),
diff --git a/datafusion/functions-nested/src/max.rs
b/datafusion/functions-nested/src/max.rs
new file mode 100644
index 0000000000..22bd14740b
--- /dev/null
+++ b/datafusion/functions-nested/src/max.rs
@@ -0,0 +1,137 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+//! [`ScalarUDFImpl`] definitions for array_max function.
+use crate::utils::make_scalar_function;
+use arrow::array::ArrayRef;
+use arrow::datatypes::DataType;
+use arrow::datatypes::DataType::List;
+use datafusion_common::cast::as_list_array;
+use datafusion_common::utils::take_function_args;
+use datafusion_common::{exec_err, ScalarValue};
+use datafusion_doc::Documentation;
+use datafusion_expr::{ColumnarValue, ScalarUDFImpl, Signature, Volatility};
+use datafusion_functions_aggregate::min_max;
+use datafusion_macros::user_doc;
+use itertools::Itertools;
+use std::any::Any;
+
+make_udf_expr_and_func!(
+ ArrayMax,
+ array_max,
+ array,
+ "returns the maximum value in the array.",
+ array_max_udf
+);
+
+#[user_doc(
+ doc_section(label = "Array Functions"),
+ description = "Returns the maximum value in the array.",
+ syntax_example = "array_max(array)",
+ sql_example = r#"```sql
+> select array_max([3,1,4,2]);
++-----------------------------------------+
+| array_max(List([3,1,4,2])) |
++-----------------------------------------+
+| 4 |
++-----------------------------------------+
+```"#,
+ argument(
+ name = "array",
+ description = "Array expression. Can be a constant, column, or
function, and any combination of array operators."
+ )
+)]
+#[derive(Debug)]
+pub struct ArrayMax {
+ signature: Signature,
+ aliases: Vec<String>,
+}
+
+impl Default for ArrayMax {
+ fn default() -> Self {
+ Self::new()
+ }
+}
+
+impl ArrayMax {
+ pub fn new() -> Self {
+ Self {
+ signature: Signature::array(Volatility::Immutable),
+ aliases: vec!["list_max".to_string()],
+ }
+ }
+}
+
+impl ScalarUDFImpl for ArrayMax {
+ fn as_any(&self) -> &dyn Any {
+ self
+ }
+
+ fn name(&self) -> &str {
+ "array_max"
+ }
+
+ fn signature(&self) -> &Signature {
+ &self.signature
+ }
+
+ fn return_type(&self, arg_types: &[DataType]) ->
datafusion_common::Result<DataType> {
+ match &arg_types[0] {
+ List(field) => Ok(field.data_type().clone()),
+ _ => exec_err!("Not reachable, data_type should be List"),
+ }
+ }
+
+ fn invoke_batch(
+ &self,
+ args: &[ColumnarValue],
+ _number_rows: usize,
+ ) -> datafusion_common::Result<ColumnarValue> {
+ make_scalar_function(array_max_inner)(args)
+ }
+
+ fn aliases(&self) -> &[String] {
+ &self.aliases
+ }
+
+ fn documentation(&self) -> Option<&Documentation> {
+ self.doc()
+ }
+}
+
+/// array_max SQL function
+///
+/// There is one argument for array_max as the array.
+/// `array_max(array)`
+///
+/// For example:
+/// > array_max(\[1, 3, 2]) -> 3
+pub fn array_max_inner(args: &[ArrayRef]) ->
datafusion_common::Result<ArrayRef> {
+ let [arg1] = take_function_args("array_max", args)?;
+
+ match arg1.data_type() {
+ List(_) => {
+ let input_list_array = as_list_array(&arg1)?;
+ let result_vec = input_list_array
+ .iter()
+ .flat_map(|arr| min_max::max_batch(&arr.unwrap()))
+ .collect_vec();
+ ScalarValue::iter_to_array(result_vec)
+ }
+ _ => exec_err!("array_max does not support type: {:?}",
arg1.data_type()),
+ }
+}
diff --git a/datafusion/sqllogictest/test_files/array.slt
b/datafusion/sqllogictest/test_files/array.slt
index c8f6a985bb..3b7f129606 100644
--- a/datafusion/sqllogictest/test_files/array.slt
+++ b/datafusion/sqllogictest/test_files/array.slt
@@ -1435,6 +1435,93 @@ NULL 23
NULL 43
5 NULL
+
+## array_max
+# array_max scalar function #1 (with positive index)
+query I
+select array_max(make_array(5, 3, 6, 4));
+----
+6
+
+query I
+select array_max(make_array(5, 3, 4, NULL, 6, NULL));
+----
+6
+
+query I
+select array_max(make_array(NULL, NULL));
+----
+NULL
+
+query T
+select array_max(make_array('h', 'e', 'o', 'l', 'l'));
+----
+o
+
+query T
+select array_max(make_array('h', 'e', 'l', NULL, 'l', 'o', NULL));
+----
+o
+
+query B
+select array_max(make_array(false, true, false, true));
+----
+true
+
+query B
+select array_max(make_array(false, true, NULL, false, true));
+----
+true
+
+query D
+select array_max(make_array(DATE '1992-09-01', DATE '1993-03-01', DATE
'1999-05-01', DATE '1985-11-01'));
+----
+1999-05-01
+
+query D
+select array_max(make_array(DATE '1995-09-01', DATE '1999-05-01', DATE
'1993-03-01', NULL));
+----
+1999-05-01
+
+query P
+select array_max(make_array(TIMESTAMP '1992-09-01', TIMESTAMP '1995-06-01',
TIMESTAMP '1984-10-01'));
+----
+1995-06-01T00:00:00
+
+query P
+select array_max(make_array(NULL, TIMESTAMP '1996-10-01', TIMESTAMP
'1995-06-01'));
+----
+1996-10-01T00:00:00
+
+query R
+select array_max(make_array(5.1, -3.2, 6.3, 4.9));
+----
+6.3
+
+query ?I
+select input, array_max(input) from (select make_array(d - 1, d, d + 1) input
from (values (0), (10), (20), (30), (NULL)) t(d))
+----
+[-1, 0, 1] 1
+[9, 10, 11] 11
+[19, 20, 21] 21
+[29, 30, 31] 31
+[NULL, NULL, NULL] NULL
+
+query II
+select array_max(arrow_cast(make_array(1, 2, 3), 'FixedSizeList(3, Int64)')),
array_max(arrow_cast(make_array(1), 'FixedSizeList(1, Int64)'));
+----
+3 1
+
+query I
+select array_max(make_array());
+----
+NULL
+
+# Testing with empty arguments should result in an error
+query error DataFusion error: Error during planning: 'array_max' does not
support zero arguments
+select array_max();
+
+
## array_pop_back (aliases: `list_pop_back`)
# array_pop_back scalar function with null
diff --git a/docs/source/user-guide/sql/scalar_functions.md
b/docs/source/user-guide/sql/scalar_functions.md
index fb4043c33e..60ecf7bd78 100644
--- a/docs/source/user-guide/sql/scalar_functions.md
+++ b/docs/source/user-guide/sql/scalar_functions.md
@@ -2524,6 +2524,7 @@ _Alias of [current_date](#current_date)._
- [array_intersect](#array_intersect)
- [array_join](#array_join)
- [array_length](#array_length)
+- [array_max](#array_max)
- [array_ndims](#array_ndims)
- [array_pop_back](#array_pop_back)
- [array_pop_front](#array_pop_front)
@@ -2569,6 +2570,7 @@ _Alias of [current_date](#current_date)._
- [list_intersect](#list_intersect)
- [list_join](#list_join)
- [list_length](#list_length)
+- [list_max](#list_max)
- [list_ndims](#list_ndims)
- [list_pop_back](#list_pop_back)
- [list_pop_front](#list_pop_front)
@@ -3002,6 +3004,33 @@ array_length(array, dimension)
- list_length
+### `array_max`
+
+Returns the maximum value in the array.
+
+```sql
+array_max(array)
+```
+
+#### Arguments
+
+- **array**: Array expression. Can be a constant, column, or function, and any
combination of array operators.
+
+#### Example
+
+```sql
+> select array_max([3,1,4,2]);
++-----------------------------------------+
+| array_max(List([3,1,4,2])) |
++-----------------------------------------+
+| 4 |
++-----------------------------------------+
+```
+
+#### Aliases
+
+- list_max
+
### `array_ndims`
Returns the number of dimensions of the array.
@@ -3759,6 +3788,10 @@ _Alias of [array_to_string](#array_to_string)._
_Alias of [array_length](#array_length)._
+### `list_max`
+
+_Alias of [array_max](#array_max)._
+
### `list_ndims`
_Alias of [array_ndims](#array_ndims)._
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