Add to_date function

datafusion-examples/examples/to_date.rs

@@ -0,0 +1,60 @@
+// 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::sync::Arc;
+
+use datafusion::arrow::array::StringArray;
+use datafusion::arrow::datatypes::{DataType, Field, Schema};
+use datafusion::arrow::record_batch::RecordBatch;
+use datafusion::error::Result;
+use datafusion::prelude::*;
+
+/// This example demonstrates how to use the to_date series
+/// of functions in the DataFrame API as well as via sql.
+#[tokio::main]
+async fn main() -> Result<()> {
+    // define a schema.
+    let schema = Arc::new(Schema::new(vec![Field::new("a", DataType::Utf8, false)]));
+
+    // define data.
+    let batch = RecordBatch::try_new(
+        schema,
+        vec![Arc::new(StringArray::from(vec![
+            "2020-09-08T13:42:29Z",
+            "2020-09-08T13:42:29.190855-05:00",
+            "2020-08-09 12:13:29",
+            "2020-01-02",
+        ]))],
+    )?;
+
+    // declare a new context. In spark API, this corresponds to a new spark SQLsession
+    let ctx = SessionContext::new();
+
+    // declare a table in memory. In spark API, this corresponds to createDataFrame(...).
+    ctx.register_batch("t", batch)?;
+    let df = ctx.table("t").await?;
+
+    // use to_date function to convert col 'a' to timestamp type using the default parsing
+    let df = df.with_column("a", to_date(vec![col("a")]))?;
+
+    let df = df.select_columns(&["a"])?;
+
+    // print the results
+    df.show().await?;
+
+    Ok(())
+}

datafusion/common/src/scalar/mod.rs

@@ -45,7 +45,7 @@ use arrow::{
     compute::kernels::cast::{cast_with_options, CastOptions},
     datatypes::{
         i256, ArrowDictionaryKeyType, ArrowNativeType, ArrowTimestampType, DataType,
-        Field, Float32Type, Int16Type, Int32Type, Int64Type, Int8Type,
+        Date32Type, Field, Float32Type, Int16Type, Int32Type, Int64Type, Int8Type,
         IntervalDayTimeType, IntervalMonthDayNanoType, IntervalUnit,
         IntervalYearMonthType, TimeUnit, TimestampMicrosecondType,
         TimestampMillisecondType, TimestampNanosecondType, TimestampSecondType,
@@ -3317,6 +3317,12 @@ impl ScalarType<i64> for TimestampNanosecondType {
     }
 }
 
+impl ScalarType<i32> for Date32Type {
+    fn scalar(r: Option<i32>) -> ScalarValue {
+        ScalarValue::Date32(r)
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use std::cmp::Ordering;

datafusion/expr/src/built_in_function.rs

@@ -275,6 +275,8 @@ pub enum BuiltinScalarFunction {
     ToTimestampSeconds,
     /// from_unixtime
     FromUnixtime,
+    /// to_date
+    ToDate,
     ///now
     Now,
     ///current_date
@@ -472,6 +474,7 @@ impl BuiltinScalarFunction {
             BuiltinScalarFunction::Upper => Volatility::Immutable,
             BuiltinScalarFunction::Struct => Volatility::Immutable,
             BuiltinScalarFunction::FromUnixtime => Volatility::Immutable,
+            BuiltinScalarFunction::ToDate => Volatility::Immutable,
             BuiltinScalarFunction::ArrowTypeof => Volatility::Immutable,
             BuiltinScalarFunction::OverLay => Volatility::Immutable,
             BuiltinScalarFunction::Levenshtein => Volatility::Immutable,
@@ -781,6 +784,7 @@ impl BuiltinScalarFunction {
             BuiltinScalarFunction::ToTimestampMicros => Ok(Timestamp(Microsecond, None)),
             BuiltinScalarFunction::ToTimestampSeconds => Ok(Timestamp(Second, None)),
             BuiltinScalarFunction::FromUnixtime => Ok(Timestamp(Second, None)),
+            BuiltinScalarFunction::ToDate => Ok(Date32),
             BuiltinScalarFunction::Now => {
                 Ok(Timestamp(Nanosecond, Some("+00:00".into())))
             }
@@ -1058,6 +1062,7 @@ impl BuiltinScalarFunction {
             BuiltinScalarFunction::FromUnixtime => {
                 Signature::uniform(1, vec![Int64], self.volatility())
             }
+            BuiltinScalarFunction::ToDate => Signature::variadic_any(self.volatility()),
             BuiltinScalarFunction::Digest => Signature::one_of(
                 vec![
                     Exact(vec![Utf8, Utf8]),
@@ -1490,6 +1495,7 @@ impl BuiltinScalarFunction {
             BuiltinScalarFunction::ToTimestampSeconds => &["to_timestamp_seconds"],
             BuiltinScalarFunction::ToTimestampNanos => &["to_timestamp_nanos"],
             BuiltinScalarFunction::FromUnixtime => &["from_unixtime"],
+            BuiltinScalarFunction::ToDate => &["to_date"],
 
             // hashing functions
             BuiltinScalarFunction::Digest => &["digest"],

datafusion/expr/src/expr_fn.rs

@@ -881,6 +881,11 @@ scalar_expr!(
     datetime format,
     "converts a date, time, timestamp or duration to a string based on the provided format"
 );
+nary_scalar_expr!(
+    ToDate,
+    to_date,
+    "converts string to date according to the given format"
+);
 nary_scalar_expr!(
     ToTimestamp,
     to_timestamp,

datafusion/physical-expr/src/datetime_expressions.rs

@@ -54,7 +54,8 @@ use datafusion_common::cast::{
     as_timestamp_nanosecond_array, as_timestamp_second_array,
 };
 use datafusion_common::{
-    exec_err, not_impl_err, DataFusionError, Result, ScalarType, ScalarValue,
+    exec_err, internal_datafusion_err, not_impl_err, DataFusionError, Result, ScalarType,
+    ScalarValue,
 };
 use datafusion_expr::ColumnarValue;
 
@@ -424,6 +425,84 @@ fn to_timestamp_impl<T: ArrowTimestampType + ScalarType<i64>>(
     }
 }
 
+/// # Examples
+///
+/// ```ignore
+/// # use std::sync::Arc;
+
+/// # use datafusion::arrow::array::StringArray;
+/// # use datafusion::arrow::datatypes::{DataType, Field, Schema};
+/// # use datafusion::arrow::record_batch::RecordBatch;
+/// # use datafusion::error::Result;
+/// # use datafusion::prelude::*;
+
+/// # #[tokio::main]
+/// # async fn main() -> Result<()> {
+///     // define a schema.
+///     let schema = Arc::new(Schema::new(vec![Field::new("a", DataType::Utf8, false)]));
+
+///     // define data.
+///     let batch = RecordBatch::try_new(
+///         schema,
+///         vec![Arc::new(StringArray::from(vec![
+///             "2020-09-08T13:42:29Z",
+///             "2020-09-08T13:42:29.190855-05:00",
+///             "2020-08-09 12:13:29",
+///             "2020-01-02",
+///         ]))],
+///     )?;
+
+///     // declare a new context. In spark API, this corresponds to a new spark SQLsession
+///     let ctx = SessionContext::new();
+
+///     // declare a table in memory. In spark API, this corresponds to createDataFrame(...).
+///     ctx.register_batch("t", batch)?;
+///     let df = ctx.table("t").await?;
+
+///     // use to_date function to convert col 'a' to timestamp type using the default parsing
+///     let df = df.with_column("a", to_date(vec![col("a")]))?;
+
+///     let df = df.select_columns(&["a"])?;
+
+///     // print the results
+///     df.show().await?;
+
+///     # Ok(())
+/// # }
+/// ```
+pub fn to_date(args: &[ColumnarValue]) -> Result<ColumnarValue> {
+    match args.len() {
+        1 => handle::<Date32Type, _, Date32Type>(
+            args,
+            |s| {
+                string_to_timestamp_nanos_shim(s)
+                    .map(|n| n / (1_000_000 * 24 * 60 * 60 * 1_000))
+                    .and_then(|v| {
+                        v.try_into().map_err(|_| {
+                            internal_datafusion_err!("Unable to cast to Date32 for converting from i64 to i32 failed")
+                        })
+                    })
+            },
+            "to_date",
+        ),
+        n if n >= 2 => handle_multiple::<Date32Type, _, Date32Type, _>(
+            args,
+            |s, format| {
+                string_to_timestamp_nanos_formatted(s, format)
+                    .map(|n| n / (1_000_000 * 24 * 60 * 60 * 1_000))
+                    .and_then(|v| {
+                        v.try_into().map_err(|_| {
+                            internal_datafusion_err!("Unable to cast to Date32 for converting from i64 to i32 failed")
+                        })
+                    })
+            },
+            |n| n,
+            "to_date",
+        ),
+        _ => exec_err!("Unsupported 0 argument count for function to_date"),
+    }
+}
+
 /// to_timestamp SQL function
 ///
 /// Note: `to_timestamp` returns `Timestamp(Nanosecond)` though its arguments are interpreted as **seconds**.
@@ -1567,6 +1646,36 @@ fn validate_to_timestamp_data_types(
     None
 }
 
+/// to_date SQL function implementation
+pub fn to_date_invoke(args: &[ColumnarValue]) -> Result<ColumnarValue> {
+    if args.is_empty() {
+        return exec_err!(
+            "to_date function requires 1 or more arguments, got {}",
+            args.len()
+        );
+    }
+
+    // validate that any args after the first one are Utf8
+    if args.len() > 1 {
+        if let Some(value) = validate_to_timestamp_data_types(args, "to_date") {
+            return value;
+        }
+    }
+
+    match args[0].data_type() {
+        DataType::Int32
+        | DataType::Int64
+        | DataType::Null
+        | DataType::Float64
+        | DataType::Date32
+        | DataType::Date64 => cast_column(&args[0], &DataType::Date32, None),
+        DataType::Utf8 => to_date(args),
+        other => {
+            exec_err!("Unsupported data type {:?} for function to_date", other)
+        }
+    }
+}
+
 /// to_timestamp() SQL function implementation
 pub fn to_timestamp_invoke(args: &[ColumnarValue]) -> Result<ColumnarValue> {
     if args.is_empty() {

datafusion/physical-expr/src/functions.rs

@@ -523,6 +523,7 @@ pub fn create_physical_fun(
         BuiltinScalarFunction::FromUnixtime => {
             Arc::new(datetime_expressions::from_unixtime_invoke)
         }
+        BuiltinScalarFunction::ToDate => Arc::new(datetime_expressions::to_date_invoke),
         BuiltinScalarFunction::InitCap => Arc::new(|args| match args[0].data_type() {
             DataType::Utf8 => {
                 make_scalar_function_inner(string_expressions::initcap::<i32>)(args)

datafusion/proto/proto/datafusion.proto

@@ -1,4 +1,5 @@
 /*
+
  * 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
@@ -682,6 +683,7 @@ enum ScalarFunction {
   ArrayReverse = 134;
   RegexpLike = 135;
   ToChar = 136;
+  ToDate = 137;
 }
 
 message ScalarFunctionNode {

datafusion/proto/src/logical_plan/from_proto.rs

@@ -570,6 +570,7 @@ impl From<&protobuf::ScalarFunction> for BuiltinScalarFunction {
             ScalarFunction::Levenshtein => Self::Levenshtein,
             ScalarFunction::SubstrIndex => Self::SubstrIndex,
             ScalarFunction::FindInSet => Self::FindInSet,
+            ScalarFunction::ToDate => Self::ToDate,
         }
     }
 }
@@ -1810,6 +1811,16 @@ pub fn parse_expr(
                 ScalarFunction::StructFun => {
                     Ok(struct_fun(parse_expr(&args[0], registry)?))
                 }
+                ScalarFunction::ToDate => {
+                    let args: Vec<_> = args
+                        .iter()
+                        .map(|expr| parse_expr(expr, registry))
+                        .collect::<std::result::Result<_, _>>()?;
+                    Ok(Expr::ScalarFunction(expr::ScalarFunction::new(
+                        BuiltinScalarFunction::ToDate,
+                        args,
+                    )))
+                }
             }
         }
         ExprType::ScalarUdfExpr(protobuf::ScalarUdfExprNode { fun_name, args }) => {

datafusion/proto/src/logical_plan/to_proto.rs

@@ -1549,6 +1549,7 @@ impl TryFrom<&BuiltinScalarFunction> for protobuf::ScalarFunction {
             BuiltinScalarFunction::Levenshtein => Self::Levenshtein,
             BuiltinScalarFunction::SubstrIndex => Self::SubstrIndex,
             BuiltinScalarFunction::FindInSet => Self::FindInSet,
+            BuiltinScalarFunction::ToDate => Self::ToDate,
         };
 
         Ok(scalar_function)