risingwave_expr_impl/scalar/
array_distinct.rs

1// Copyright 2025 RisingWave Labs
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15use itertools::Itertools;
16use risingwave_common::array::*;
17use risingwave_expr::function;
18
19/// Returns a new array removing all the duplicates from the input array
20///
21/// ```sql
22/// array_distinct (array anyarray) → array
23/// ```
24///
25/// Examples:
26///
27/// ```slt
28/// query T
29/// select array_distinct(array[NULL]);
30/// ----
31/// {NULL}
32///
33/// query T
34/// select array_distinct(array[1,2,1,1]);
35/// ----
36/// {1,2}
37///
38/// query T
39/// select array_distinct(array[1,2,1,NULL]);
40/// ----
41/// {1,2,NULL}
42///
43/// query T
44/// select array_distinct(null::int[]);
45/// ----
46/// NULL
47///
48/// query error polymorphic type
49/// select array_distinct(null);
50/// ```
51
52#[function("array_distinct(anyarray) -> anyarray")]
53pub fn array_distinct(list: ListRef<'_>) -> ListValue {
54    ListValue::from_datum_iter(&list.data_type(), list.iter().unique())
55}
56
57#[cfg(test)]
58mod tests {
59    use risingwave_common::types::Scalar;
60
61    use super::*;
62
63    #[test]
64    fn test_array_distinct_array_of_primitives() {
65        let array = ListValue::from_iter([42, 43, 42]);
66        let expected = ListValue::from_iter([42, 43]);
67        let actual = array_distinct(array.as_scalar_ref());
68        assert_eq!(actual, expected);
69    }
70
71    // More test cases are in e2e tests.
72}
risingwave_expr_impl/scalar/array_distinct.rs

risingwave_expr_impl/scalar/
array_distinct.rs
