cht42 commented on code in PR #19829: URL: https://github.com/apache/datafusion/pull/19829#discussion_r2696875352
########## datafusion/spark/src/function/datetime/date_trunc.rs: ########## @@ -0,0 +1,131 @@ +// 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. + +use std::any::Any; +use std::sync::Arc; + +use arrow::datatypes::{DataType, Field, FieldRef, TimeUnit}; +use datafusion_common::types::{NativeType, logical_string}; +use datafusion_common::utils::take_function_args; +use datafusion_common::{Result, ScalarValue, internal_err}; +use datafusion_expr::expr::ScalarFunction; +use datafusion_expr::simplify::{ExprSimplifyResult, SimplifyContext}; +use datafusion_expr::{ + Coercion, ColumnarValue, Expr, ReturnFieldArgs, ScalarFunctionArgs, ScalarUDFImpl, + Signature, TypeSignatureClass, Volatility, +}; + +/// Spark date_trunc supports extra format aliases. +/// <https://spark.apache.org/docs/latest/api/sql/index.html#date_trunc> +#[derive(Debug, PartialEq, Eq, Hash)] +pub struct SparkDateTrunc { + signature: Signature, +} + +impl Default for SparkDateTrunc { + fn default() -> Self { + Self::new() + } +} + +impl SparkDateTrunc { + pub fn new() -> Self { + Self { + signature: Signature::coercible( + vec![ + Coercion::new_exact(TypeSignatureClass::Native(logical_string())), + Coercion::new_implicit( + TypeSignatureClass::Timestamp, + vec![TypeSignatureClass::Native(logical_string())], + NativeType::Timestamp(TimeUnit::Microsecond, None), + ), + ], + Volatility::Immutable, + ), + } + } +} + +impl ScalarUDFImpl for SparkDateTrunc { + fn as_any(&self) -> &dyn Any { + self + } + + fn name(&self) -> &str { + "date_trunc" + } + + fn signature(&self) -> &Signature { + &self.signature + } + + fn return_type(&self, _arg_types: &[DataType]) -> Result<DataType> { + internal_err!("return_field_from_args should be used instead") + } + + fn return_field_from_args(&self, args: ReturnFieldArgs) -> Result<FieldRef> { + let nullable = args.arg_fields.iter().any(|f| f.is_nullable()); + + Ok(Arc::new(Field::new( + self.name(), + args.arg_fields[1].data_type().clone(), + nullable, + ))) + } + + fn invoke_with_args(&self, _args: ScalarFunctionArgs) -> Result<ColumnarValue> { + internal_err!( + "spark date_trunc should have been simplified to standard date_trunc" + ) + } + + fn simplify( + &self, + args: Vec<Expr>, + _info: &SimplifyContext, + ) -> Result<ExprSimplifyResult> { + let [fmt_expr, ts_expr] = take_function_args(self.name(), args)?; + + let fmt = match fmt_expr.as_literal() { + Some(ScalarValue::Utf8(Some(v))) + | Some(ScalarValue::Utf8View(Some(v))) + | Some(ScalarValue::LargeUtf8(Some(v))) => v.to_lowercase(), + _ => { + return internal_err!( + "First argument of `DATE_TRUNC` must be non-null scalar Utf8" + ); + } + }; + + // Map Spark-specific fmt aliases to datafusion ones + let fmt = match fmt.as_str() { + "yy" | "yyyy" => "year", + "mm" | "mon" => "month", + "dd" => "day", + other => other, + }; + + let fmt_expr = Expr::Literal(ScalarValue::new_utf8(fmt), None); + + Ok(ExprSimplifyResult::Simplified(Expr::ScalarFunction( + ScalarFunction::new_udf( + datafusion_functions::datetime::date_trunc(), Review Comment: done -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
