feat(spark): implement Spark date_diff function

datafusion/spark/src/function/datetime/date_diff.rs

@@ -0,0 +1,118 @@
+// 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};
+use datafusion_common::types::{NativeType, logical_date, logical_string};
+use datafusion_common::utils::take_function_args;
+use datafusion_common::{Result, internal_err};
+use datafusion_expr::simplify::{ExprSimplifyResult, SimplifyContext};
+use datafusion_expr::{
+    Coercion, ColumnarValue, Expr, ExprSchemable, Operator, ReturnFieldArgs,
+    ScalarFunctionArgs, ScalarUDFImpl, Signature, TypeSignatureClass, Volatility,
+    binary_expr,
+};
+
+/// <https://spark.apache.org/docs/latest/api/sql/index.html#date_diff>
+#[derive(Debug, PartialEq, Eq, Hash)]
+pub struct SparkDateDiff {
+    signature: Signature,
+    aliases: Vec<String>,
+}
+
+impl Default for SparkDateDiff {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl SparkDateDiff {
+    pub fn new() -> Self {
+        Self {
+            signature: Signature::coercible(
+                vec![
+                    Coercion::new_implicit(
+                        TypeSignatureClass::Native(logical_date()),
+                        vec![
+                            TypeSignatureClass::Native(logical_string()),
+                            TypeSignatureClass::Timestamp,
+                        ],
+                        NativeType::Date,
+                    ),
+                    Coercion::new_implicit(
+                        TypeSignatureClass::Native(logical_date()),
+                        vec![
+                            TypeSignatureClass::Native(logical_string()),
+                            TypeSignatureClass::Timestamp,
+                        ],
+                        NativeType::Date,
+                    ),
+                ],
+                Volatility::Immutable,
+            ),
+            aliases: vec!["datediff".to_string()],
+        }
+    }
+}
+
+impl ScalarUDFImpl for SparkDateDiff {
+    fn as_any(&self) -> &dyn Any {
+        self
+    }
+
+    fn name(&self) -> &str {
+        "date_diff"
+    }
+
+    fn aliases(&self) -> &[String] {
+        &self.aliases
+    }
+
+    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(), DataType::Int32, nullable)))
+    }
+
+    fn invoke_with_args(&self, _args: ScalarFunctionArgs) -> Result<ColumnarValue> {
+        internal_err!(
+            "spark date_diff should have been simplified to standard subtraction"
+        )
+    }
+
+    fn simplify(
+        &self,
+        args: Vec<Expr>,
+        info: &SimplifyContext,
+    ) -> Result<ExprSimplifyResult> {
+        let [end, start] = take_function_args(self.name(), args)?;
+        Ok(ExprSimplifyResult::Simplified(binary_expr(
+            end.cast_to(&DataType::Int32, info.schema())?,
+            Operator::Minus,
+            start.cast_to(&DataType::Int32, info.schema())?,
+        )))
+    }
+}

datafusion/spark/src/function/datetime/mod.rs

@@ -16,6 +16,7 @@
 // under the License.
 
 pub mod date_add;
+pub mod date_diff;
 pub mod date_sub;
 pub mod extract;
 pub mod last_day;
@@ -36,6 +37,7 @@ make_udf_function!(last_day::SparkLastDay, last_day);
 make_udf_function!(make_dt_interval::SparkMakeDtInterval, make_dt_interval);
 make_udf_function!(make_interval::SparkMakeInterval, make_interval);
 make_udf_function!(next_day::SparkNextDay, next_day);
+make_udf_function!(date_diff::SparkDateDiff, date_diff);
 
 pub mod expr_fn {
     use datafusion_functions::export_functions;
@@ -83,6 +85,11 @@ pub mod expr_fn {
         "Returns the first date which is later than start_date and named as indicated. The function returns NULL if at least one of the input parameters is NULL.",
         arg1 arg2
     ));
+    export_functions!((
+        date_diff,
+        "Returns the number of days from start `start` to end `end`.",
+        end start
+    ));
 }
 
 pub fn functions() -> Vec<Arc<ScalarUDF>> {
@@ -96,5 +103,6 @@ pub fn functions() -> Vec<Arc<ScalarUDF>> {
         make_dt_interval(),
         make_interval(),
         next_day(),
+        date_diff(),
     ]
 }

datafusion/sqllogictest/test_files/spark/datetime/date_diff.slt

@@ -15,18 +15,100 @@
 # specific language governing permissions and limitations
 # under the License.
 
-# This file was originally created by a porting script from:
-#   https://github.com/lakehq/sail/tree/43b6ed8221de5c4c4adbedbb267ae1351158b43c/crates/sail-spark-connect/tests/gold_data/function
-# This file is part of the implementation of the datafusion-spark function library.
-# For more information, please see:
-#   https://github.com/apache/datafusion/issues/15914
-
-## Original Query: SELECT date_diff('2009-07-30', '2009-07-31');
-## PySpark 3.5.5 Result: {'date_diff(2009-07-30, 2009-07-31)': -1, 'typeof(date_diff(2009-07-30, 2009-07-31))': 'int', 'typeof(2009-07-30)': 'string', 'typeof(2009-07-31)': 'string'}
-#query
-#SELECT date_diff('2009-07-30'::string, '2009-07-31'::string);
-
-## Original Query: SELECT date_diff('2009-07-31', '2009-07-30');
-## PySpark 3.5.5 Result: {'date_diff(2009-07-31, 2009-07-30)': 1, 'typeof(date_diff(2009-07-31, 2009-07-30))': 'int', 'typeof(2009-07-31)': 'string', 'typeof(2009-07-30)': 'string'}
-#query
-#SELECT date_diff('2009-07-31'::string, '2009-07-30'::string);
+# date input
+query I
+SELECT date_diff('2009-07-30'::date, '2009-07-31'::date);
+----
+-1
+
+query I
+SELECT date_diff('2009-07-31'::date, '2009-07-30'::date);
+----
+1
+
+# Same date returns 0
+query I
+SELECT date_diff('2009-07-30'::date, '2009-07-30'::date);
+----
+0
+
+# Large difference
+query I
+SELECT date_diff('2020-01-01'::date, '1970-01-01'::date);
+----
+18262
+
+# timestamp input
+query I
+SELECT date_diff('2009-07-30 12:34:56'::timestamp, '2009-07-31 23:45:01'::timestamp);
+----
+-1
+
+query I
+SELECT date_diff('2009-07-31 23:45:01'::timestamp, '2009-07-30 12:34:56'::timestamp);
+----
+1
+
+# string input
+query I
+SELECT date_diff('2009-07-30', '2009-07-31');
+----
+-1
+
+query I
+SELECT date_diff('2009-07-31', '2009-07-30');
+----
+1
+
+# NULL handling
+query I
+SELECT date_diff(NULL::date, '2009-07-30'::date);
+----
+NULL
+
+query I
+SELECT date_diff('2009-07-31'::date, NULL::date);
+----
+NULL
+
+query I
+SELECT date_diff(NULL::date, NULL::date);
+----
+NULL
+
+query I
+SELECT date_diff(column1, column2)
+FROM VALUES
+('2009-07-30'::date, '2009-07-31'::date),
+('2009-07-31'::date, '2009-07-30'::date),
+(NULL::date, '2009-07-30'::date),
+('2009-07-31'::date, NULL::date),
+(NULL::date, NULL::date);
+----
+-1
+1
+NULL
+NULL
+NULL
+
+
+# Alias datediff
+query I
+SELECT datediff('2009-07-30'::date, '2009-07-31'::date);
+----
+-1
+
+query I
+SELECT datediff(column1, column2)
+FROM VALUES
+('2009-07-30'::date, '2009-07-31'::date),
+('2009-07-31'::date, '2009-07-30'::date),
+(NULL::date, '2009-07-30'::date),
+('2009-07-31'::date, NULL::date),
+(NULL::date, NULL::date);
+----
+-1
+1
+NULL
+NULL
+NULL