datafusion_functions_aggregate/
grouping.rs

1// Licensed to the Apache Software Foundation (ASF) under one
2// or more contributor license agreements.  See the NOTICE file
3// distributed with this work for additional information
4// regarding copyright ownership.  The ASF licenses this file
5// to you under the Apache License, Version 2.0 (the
6// "License"); you may not use this file except in compliance
7// with the License.  You may obtain a copy of the License at
8//
9//   http://www.apache.org/licenses/LICENSE-2.0
10//
11// Unless required by applicable law or agreed to in writing,
12// software distributed under the License is distributed on an
13// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
14// KIND, either express or implied.  See the License for the
15// specific language governing permissions and limitations
16// under the License.
17
18//! Defines physical expressions that can evaluated at runtime during query execution
19
20use arrow::datatypes::Field;
21use arrow::datatypes::{DataType, FieldRef};
22use datafusion_common::{Result, not_impl_err};
23use datafusion_expr::function::AccumulatorArgs;
24use datafusion_expr::function::StateFieldsArgs;
25use datafusion_expr::utils::format_state_name;
26use datafusion_expr::{
27    Accumulator, AggregateUDFImpl, Documentation, Signature, Volatility,
28};
29use datafusion_macros::user_doc;
30
31make_udaf_expr_and_func!(
32    Grouping,
33    grouping,
34    expression,
35    "Returns 1 if the data is aggregated across the specified column or 0 for not aggregated in the result set.",
36    grouping_udaf
37);
38
39#[user_doc(
40    doc_section(label = "General Functions"),
41    description = "Returns 1 if the data is aggregated across the specified column, or 0 if it is not aggregated in the result set.",
42    syntax_example = "grouping(expression)",
43    sql_example = r#"```sql
44> SELECT column_name, GROUPING(column_name) AS group_column
45  FROM table_name
46  GROUP BY GROUPING SETS ((column_name), ());
47+-------------+-------------+
48| column_name | group_column |
49+-------------+-------------+
50| value1      | 0           |
51| value2      | 0           |
52| NULL        | 1           |
53+-------------+-------------+
54```"#,
55    argument(
56        name = "expression",
57        description = "Expression to evaluate whether data is aggregated across the specified column. Can be a constant, column, or function."
58    )
59)]
60#[derive(PartialEq, Eq, Hash, Debug)]
61pub struct Grouping {
62    signature: Signature,
63}
64
65impl Default for Grouping {
66    fn default() -> Self {
67        Self::new()
68    }
69}
70
71impl Grouping {
72    /// Create a new GROUPING aggregate function.
73    pub fn new() -> Self {
74        Self {
75            signature: Signature::variadic_any(Volatility::Immutable),
76        }
77    }
78}
79
80impl AggregateUDFImpl for Grouping {
81    fn name(&self) -> &str {
82        "grouping"
83    }
84
85    fn signature(&self) -> &Signature {
86        &self.signature
87    }
88
89    fn return_type(&self, _arg_types: &[DataType]) -> Result<DataType> {
90        Ok(DataType::Int32)
91    }
92
93    fn state_fields(&self, args: StateFieldsArgs) -> Result<Vec<FieldRef>> {
94        Ok(vec![
95            Field::new(
96                format_state_name(args.name, "grouping"),
97                DataType::Int32,
98                true,
99            )
100            .into(),
101        ])
102    }
103
104    fn accumulator(&self, _acc_args: AccumulatorArgs) -> Result<Box<dyn Accumulator>> {
105        not_impl_err!(
106            "physical plan is not yet implemented for GROUPING aggregate function"
107        )
108    }
109
110    fn documentation(&self) -> Option<&Documentation> {
111        self.doc()
112    }
113}
datafusion_functions_aggregate/grouping.rs

datafusion_functions_aggregate/
grouping.rs
