datafusion_spark/function/datetime/
trunc.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
18use std::any::Any;
19use std::sync::Arc;
20
21use arrow::datatypes::{DataType, Field, FieldRef, TimeUnit};
22use datafusion_common::types::{NativeType, logical_date, logical_string};
23use datafusion_common::utils::take_function_args;
24use datafusion_common::{Result, ScalarValue, internal_err, plan_err};
25use datafusion_expr::expr::ScalarFunction;
26use datafusion_expr::simplify::{ExprSimplifyResult, SimplifyContext};
27use datafusion_expr::{
28    Coercion, ColumnarValue, Expr, ExprSchemable, ReturnFieldArgs, ScalarFunctionArgs,
29    ScalarUDFImpl, Signature, TypeSignatureClass, Volatility,
30};
31
32/// Spark trunc supports date inputs only and extra format aliases.
33/// Also spark trunc's argument order is (date, format).
34/// <https://spark.apache.org/docs/latest/api/sql/index.html#trunc>
35#[derive(Debug, PartialEq, Eq, Hash)]
36pub struct SparkTrunc {
37    signature: Signature,
38}
39
40impl Default for SparkTrunc {
41    fn default() -> Self {
42        Self::new()
43    }
44}
45
46impl SparkTrunc {
47    pub fn new() -> Self {
48        Self {
49            signature: Signature::coercible(
50                vec![
51                    Coercion::new_implicit(
52                        TypeSignatureClass::Native(logical_date()),
53                        vec![TypeSignatureClass::Native(logical_string())],
54                        NativeType::Date,
55                    ),
56                    Coercion::new_exact(TypeSignatureClass::Native(logical_string())),
57                ],
58                Volatility::Immutable,
59            ),
60        }
61    }
62}
63
64impl ScalarUDFImpl for SparkTrunc {
65    fn as_any(&self) -> &dyn Any {
66        self
67    }
68
69    fn name(&self) -> &str {
70        "trunc"
71    }
72
73    fn signature(&self) -> &Signature {
74        &self.signature
75    }
76
77    fn return_type(&self, _arg_types: &[DataType]) -> Result<DataType> {
78        internal_err!("return_field_from_args should be used instead")
79    }
80
81    fn return_field_from_args(&self, args: ReturnFieldArgs) -> Result<FieldRef> {
82        let nullable = args.arg_fields.iter().any(|f| f.is_nullable());
83
84        Ok(Arc::new(Field::new(
85            self.name(),
86            args.arg_fields[0].data_type().clone(),
87            nullable,
88        )))
89    }
90
91    fn invoke_with_args(&self, _args: ScalarFunctionArgs) -> Result<ColumnarValue> {
92        internal_err!("spark trunc should have been simplified to standard date_trunc")
93    }
94
95    fn simplify(
96        &self,
97        args: Vec<Expr>,
98        info: &SimplifyContext,
99    ) -> Result<ExprSimplifyResult> {
100        let [dt_expr, fmt_expr] = take_function_args(self.name(), args)?;
101
102        let fmt = match fmt_expr.as_literal() {
103            Some(ScalarValue::Utf8(Some(v)))
104            | Some(ScalarValue::Utf8View(Some(v)))
105            | Some(ScalarValue::LargeUtf8(Some(v))) => v.to_lowercase(),
106            _ => {
107                return plan_err!(
108                    "Second argument of `TRUNC` must be non-null scalar Utf8"
109                );
110            }
111        };
112
113        // Map Spark-specific fmt aliases to datafusion ones
114        let fmt = match fmt.as_str() {
115            "yy" | "yyyy" => "year",
116            "mm" | "mon" => "month",
117            "year" | "month" | "day" | "week" | "quarter" => fmt.as_str(),
118            _ => {
119                return plan_err!(
120                    "The format argument of `TRUNC` must be one of: year, yy, yyyy, month, mm, mon, day, week, quarter."
121                );
122            }
123        };
124        let return_type = dt_expr.get_type(info.schema())?;
125
126        let fmt_expr = Expr::Literal(ScalarValue::new_utf8(fmt), None);
127
128        // Spark uses Dates so we need to cast to timestamp and back to work with datafusion's date_trunc
129        Ok(ExprSimplifyResult::Simplified(
130            Expr::ScalarFunction(ScalarFunction::new_udf(
131                datafusion_functions::datetime::date_trunc(),
132                vec![
133                    fmt_expr,
134                    dt_expr.cast_to(
135                        &DataType::Timestamp(TimeUnit::Nanosecond, None),
136                        info.schema(),
137                    )?,
138                ],
139            ))
140            .cast_to(&return_type, info.schema())?,
141        ))
142    }
143}
datafusion_spark/function/datetime/trunc.rs

datafusion_spark/function/datetime/
trunc.rs
