datafusion_physical_expr/expressions/
cast.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::fmt;
20use std::hash::Hash;
21use std::sync::Arc;
22
23use crate::physical_expr::PhysicalExpr;
24
25use arrow::compute::{can_cast_types, CastOptions};
26use arrow::datatypes::{DataType, DataType::*, FieldRef, Schema};
27use arrow::record_batch::RecordBatch;
28use datafusion_common::format::DEFAULT_FORMAT_OPTIONS;
29use datafusion_common::{not_impl_err, Result};
30use datafusion_expr_common::columnar_value::ColumnarValue;
31use datafusion_expr_common::interval_arithmetic::Interval;
32use datafusion_expr_common::sort_properties::ExprProperties;
33
34const DEFAULT_CAST_OPTIONS: CastOptions<'static> = CastOptions {
35    safe: false,
36    format_options: DEFAULT_FORMAT_OPTIONS,
37};
38
39const DEFAULT_SAFE_CAST_OPTIONS: CastOptions<'static> = CastOptions {
40    safe: true,
41    format_options: DEFAULT_FORMAT_OPTIONS,
42};
43
44/// CAST expression casts an expression to a specific data type and returns a runtime error on invalid cast
45#[derive(Debug, Clone, Eq)]
46pub struct CastExpr {
47    /// The expression to cast
48    pub expr: Arc<dyn PhysicalExpr>,
49    /// The data type to cast to
50    cast_type: DataType,
51    /// Cast options
52    cast_options: CastOptions<'static>,
53}
54
55// Manually derive PartialEq and Hash to work around https://github.com/rust-lang/rust/issues/78808
56impl PartialEq for CastExpr {
57    fn eq(&self, other: &Self) -> bool {
58        self.expr.eq(&other.expr)
59            && self.cast_type.eq(&other.cast_type)
60            && self.cast_options.eq(&other.cast_options)
61    }
62}
63
64impl Hash for CastExpr {
65    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
66        self.expr.hash(state);
67        self.cast_type.hash(state);
68        self.cast_options.hash(state);
69    }
70}
71
72impl CastExpr {
73    /// Create a new CastExpr
74    pub fn new(
75        expr: Arc<dyn PhysicalExpr>,
76        cast_type: DataType,
77        cast_options: Option<CastOptions<'static>>,
78    ) -> Self {
79        Self {
80            expr,
81            cast_type,
82            cast_options: cast_options.unwrap_or(DEFAULT_CAST_OPTIONS),
83        }
84    }
85
86    /// The expression to cast
87    pub fn expr(&self) -> &Arc<dyn PhysicalExpr> {
88        &self.expr
89    }
90
91    /// The data type to cast to
92    pub fn cast_type(&self) -> &DataType {
93        &self.cast_type
94    }
95
96    /// The cast options
97    pub fn cast_options(&self) -> &CastOptions<'static> {
98        &self.cast_options
99    }
100
101    /// Check if the cast is a widening cast (e.g. from `Int8` to `Int16`).
102    pub fn is_bigger_cast(&self, src: &DataType) -> bool {
103        if self.cast_type.eq(src) {
104            return true;
105        }
106        matches!(
107            (src, &self.cast_type),
108            (Int8, Int16 | Int32 | Int64)
109                | (Int16, Int32 | Int64)
110                | (Int32, Int64)
111                | (UInt8, UInt16 | UInt32 | UInt64)
112                | (UInt16, UInt32 | UInt64)
113                | (UInt32, UInt64)
114                | (
115                    Int8 | Int16 | Int32 | UInt8 | UInt16 | UInt32,
116                    Float32 | Float64
117                )
118                | (Int64 | UInt64, Float64)
119                | (Utf8, LargeUtf8)
120        )
121    }
122}
123
124impl fmt::Display for CastExpr {
125    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
126        write!(f, "CAST({} AS {:?})", self.expr, self.cast_type)
127    }
128}
129
130impl PhysicalExpr for CastExpr {
131    /// Return a reference to Any that can be used for downcasting
132    fn as_any(&self) -> &dyn Any {
133        self
134    }
135
136    fn data_type(&self, _input_schema: &Schema) -> Result<DataType> {
137        Ok(self.cast_type.clone())
138    }
139
140    fn nullable(&self, input_schema: &Schema) -> Result<bool> {
141        self.expr.nullable(input_schema)
142    }
143
144    fn evaluate(&self, batch: &RecordBatch) -> Result<ColumnarValue> {
145        let value = self.expr.evaluate(batch)?;
146        value.cast_to(&self.cast_type, Some(&self.cast_options))
147    }
148
149    fn return_field(&self, input_schema: &Schema) -> Result<FieldRef> {
150        Ok(self
151            .expr
152            .return_field(input_schema)?
153            .as_ref()
154            .clone()
155            .with_data_type(self.cast_type.clone())
156            .into())
157    }
158
159    fn children(&self) -> Vec<&Arc<dyn PhysicalExpr>> {
160        vec![&self.expr]
161    }
162
163    fn with_new_children(
164        self: Arc<Self>,
165        children: Vec<Arc<dyn PhysicalExpr>>,
166    ) -> Result<Arc<dyn PhysicalExpr>> {
167        Ok(Arc::new(CastExpr::new(
168            Arc::clone(&children[0]),
169            self.cast_type.clone(),
170            Some(self.cast_options.clone()),
171        )))
172    }
173
174    fn evaluate_bounds(&self, children: &[&Interval]) -> Result<Interval> {
175        // Cast current node's interval to the right type:
176        children[0].cast_to(&self.cast_type, &self.cast_options)
177    }
178
179    fn propagate_constraints(
180        &self,
181        interval: &Interval,
182        children: &[&Interval],
183    ) -> Result<Option<Vec<Interval>>> {
184        let child_interval = children[0];
185        // Get child's datatype:
186        let cast_type = child_interval.data_type();
187        Ok(Some(vec![
188            interval.cast_to(&cast_type, &DEFAULT_SAFE_CAST_OPTIONS)?
189        ]))
190    }
191
192    /// A [`CastExpr`] preserves the ordering of its child if the cast is done
193    /// under the same datatype family.
194    fn get_properties(&self, children: &[ExprProperties]) -> Result<ExprProperties> {
195        let source_datatype = children[0].range.data_type();
196        let target_type = &self.cast_type;
197
198        let unbounded = Interval::make_unbounded(target_type)?;
199        if (source_datatype.is_numeric() || source_datatype == Boolean)
200            && target_type.is_numeric()
201            || source_datatype.is_temporal() && target_type.is_temporal()
202            || source_datatype.eq(target_type)
203        {
204            Ok(children[0].clone().with_range(unbounded))
205        } else {
206            Ok(ExprProperties::new_unknown().with_range(unbounded))
207        }
208    }
209
210    fn fmt_sql(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
211        write!(f, "CAST(")?;
212        self.expr.fmt_sql(f)?;
213        write!(f, " AS {:?}", self.cast_type)?;
214
215        write!(f, ")")
216    }
217}
218
219/// Return a PhysicalExpression representing `expr` casted to
220/// `cast_type`, if any casting is needed.
221///
222/// Note that such casts may lose type information
223pub fn cast_with_options(
224    expr: Arc<dyn PhysicalExpr>,
225    input_schema: &Schema,
226    cast_type: DataType,
227    cast_options: Option<CastOptions<'static>>,
228) -> Result<Arc<dyn PhysicalExpr>> {
229    let expr_type = expr.data_type(input_schema)?;
230    if expr_type == cast_type {
231        Ok(Arc::clone(&expr))
232    } else if can_cast_types(&expr_type, &cast_type) {
233        Ok(Arc::new(CastExpr::new(expr, cast_type, cast_options)))
234    } else {
235        not_impl_err!("Unsupported CAST from {expr_type} to {cast_type}")
236    }
237}
238
239/// Return a PhysicalExpression representing `expr` casted to
240/// `cast_type`, if any casting is needed.
241///
242/// Note that such casts may lose type information
243pub fn cast(
244    expr: Arc<dyn PhysicalExpr>,
245    input_schema: &Schema,
246    cast_type: DataType,
247) -> Result<Arc<dyn PhysicalExpr>> {
248    cast_with_options(expr, input_schema, cast_type, None)
249}
250
251#[cfg(test)]
252mod tests {
253    use super::*;
254
255    use crate::expressions::column::col;
256
257    use arrow::{
258        array::{
259            Array, Decimal128Array, Float32Array, Float64Array, Int16Array, Int32Array,
260            Int64Array, Int8Array, StringArray, Time64NanosecondArray,
261            TimestampNanosecondArray, UInt32Array,
262        },
263        datatypes::*,
264    };
265    use datafusion_physical_expr_common::physical_expr::fmt_sql;
266    use insta::assert_snapshot;
267
268    // runs an end-to-end test of physical type cast
269    // 1. construct a record batch with a column "a" of type A
270    // 2. construct a physical expression of CAST(a AS B)
271    // 3. evaluate the expression
272    // 4. verify that the resulting expression is of type B
273    // 5. verify that the resulting values are downcastable and correct
274    macro_rules! generic_decimal_to_other_test_cast {
275        ($DECIMAL_ARRAY:ident, $A_TYPE:expr, $TYPEARRAY:ident, $TYPE:expr, $VEC:expr,$CAST_OPTIONS:expr) => {{
276            let schema = Schema::new(vec![Field::new("a", $A_TYPE, true)]);
277            let batch = RecordBatch::try_new(
278                Arc::new(schema.clone()),
279                vec![Arc::new($DECIMAL_ARRAY)],
280            )?;
281            // verify that we can construct the expression
282            let expression =
283                cast_with_options(col("a", &schema)?, &schema, $TYPE, $CAST_OPTIONS)?;
284
285            // verify that its display is correct
286            assert_eq!(
287                format!("CAST(a@0 AS {:?})", $TYPE),
288                format!("{}", expression)
289            );
290
291            // verify that the expression's type is correct
292            assert_eq!(expression.data_type(&schema)?, $TYPE);
293
294            // compute
295            let result = expression
296                .evaluate(&batch)?
297                .into_array(batch.num_rows())
298                .expect("Failed to convert to array");
299
300            // verify that the array's data_type is correct
301            assert_eq!(*result.data_type(), $TYPE);
302
303            // verify that the data itself is downcastable
304            let result = result
305                .as_any()
306                .downcast_ref::<$TYPEARRAY>()
307                .expect("failed to downcast");
308
309            // verify that the result itself is correct
310            for (i, x) in $VEC.iter().enumerate() {
311                match x {
312                    Some(x) => assert_eq!(result.value(i), *x),
313                    None => assert!(!result.is_valid(i)),
314                }
315            }
316        }};
317    }
318
319    // runs an end-to-end test of physical type cast
320    // 1. construct a record batch with a column "a" of type A
321    // 2. construct a physical expression of CAST(a AS B)
322    // 3. evaluate the expression
323    // 4. verify that the resulting expression is of type B
324    // 5. verify that the resulting values are downcastable and correct
325    macro_rules! generic_test_cast {
326        ($A_ARRAY:ident, $A_TYPE:expr, $A_VEC:expr, $TYPEARRAY:ident, $TYPE:expr, $VEC:expr, $CAST_OPTIONS:expr) => {{
327            let schema = Schema::new(vec![Field::new("a", $A_TYPE, true)]);
328            let a_vec_len = $A_VEC.len();
329            let a = $A_ARRAY::from($A_VEC);
330            let batch =
331                RecordBatch::try_new(Arc::new(schema.clone()), vec![Arc::new(a)])?;
332
333            // verify that we can construct the expression
334            let expression =
335                cast_with_options(col("a", &schema)?, &schema, $TYPE, $CAST_OPTIONS)?;
336
337            // verify that its display is correct
338            assert_eq!(
339                format!("CAST(a@0 AS {:?})", $TYPE),
340                format!("{}", expression)
341            );
342
343            // verify that the expression's type is correct
344            assert_eq!(expression.data_type(&schema)?, $TYPE);
345
346            // compute
347            let result = expression
348                .evaluate(&batch)?
349                .into_array(batch.num_rows())
350                .expect("Failed to convert to array");
351
352            // verify that the array's data_type is correct
353            assert_eq!(*result.data_type(), $TYPE);
354
355            // verify that the len is correct
356            assert_eq!(result.len(), a_vec_len);
357
358            // verify that the data itself is downcastable
359            let result = result
360                .as_any()
361                .downcast_ref::<$TYPEARRAY>()
362                .expect("failed to downcast");
363
364            // verify that the result itself is correct
365            for (i, x) in $VEC.iter().enumerate() {
366                match x {
367                    Some(x) => assert_eq!(result.value(i), *x),
368                    None => assert!(!result.is_valid(i)),
369                }
370            }
371        }};
372    }
373
374    #[test]
375    fn test_cast_decimal_to_decimal() -> Result<()> {
376        let array = vec![
377            Some(1234),
378            Some(2222),
379            Some(3),
380            Some(4000),
381            Some(5000),
382            None,
383        ];
384
385        let decimal_array = array
386            .clone()
387            .into_iter()
388            .collect::<Decimal128Array>()
389            .with_precision_and_scale(10, 3)?;
390
391        generic_decimal_to_other_test_cast!(
392            decimal_array,
393            Decimal128(10, 3),
394            Decimal128Array,
395            Decimal128(20, 6),
396            [
397                Some(1_234_000),
398                Some(2_222_000),
399                Some(3_000),
400                Some(4_000_000),
401                Some(5_000_000),
402                None
403            ],
404            None
405        );
406
407        let decimal_array = array
408            .into_iter()
409            .collect::<Decimal128Array>()
410            .with_precision_and_scale(10, 3)?;
411
412        generic_decimal_to_other_test_cast!(
413            decimal_array,
414            Decimal128(10, 3),
415            Decimal128Array,
416            Decimal128(10, 2),
417            [Some(123), Some(222), Some(0), Some(400), Some(500), None],
418            None
419        );
420
421        Ok(())
422    }
423
424    #[test]
425    fn test_cast_decimal_to_decimal_overflow() -> Result<()> {
426        let array = vec![Some(123456789)];
427
428        let decimal_array = array
429            .clone()
430            .into_iter()
431            .collect::<Decimal128Array>()
432            .with_precision_and_scale(10, 3)?;
433
434        let schema = Schema::new(vec![Field::new("a", Decimal128(10, 3), false)]);
435        let batch = RecordBatch::try_new(
436            Arc::new(schema.clone()),
437            vec![Arc::new(decimal_array)],
438        )?;
439        let expression =
440            cast_with_options(col("a", &schema)?, &schema, Decimal128(6, 2), None)?;
441        let e = expression.evaluate(&batch).unwrap_err().strip_backtrace(); // panics on OK
442        assert_snapshot!(e, @"Arrow error: Invalid argument error: 123456.79 is too large to store in a Decimal128 of precision 6. Max is 9999.99");
443        // safe cast should return null
444        let expression_safe = cast_with_options(
445            col("a", &schema)?,
446            &schema,
447            Decimal128(6, 2),
448            Some(DEFAULT_SAFE_CAST_OPTIONS),
449        )?;
450        let result_safe = expression_safe
451            .evaluate(&batch)?
452            .into_array(batch.num_rows())
453            .expect("failed to convert to array");
454
455        assert!(result_safe.is_null(0));
456
457        Ok(())
458    }
459
460    #[test]
461    fn test_cast_decimal_to_numeric() -> Result<()> {
462        let array = vec![Some(1), Some(2), Some(3), Some(4), Some(5), None];
463        // decimal to i8
464        let decimal_array = array
465            .clone()
466            .into_iter()
467            .collect::<Decimal128Array>()
468            .with_precision_and_scale(10, 0)?;
469        generic_decimal_to_other_test_cast!(
470            decimal_array,
471            Decimal128(10, 0),
472            Int8Array,
473            Int8,
474            [
475                Some(1_i8),
476                Some(2_i8),
477                Some(3_i8),
478                Some(4_i8),
479                Some(5_i8),
480                None
481            ],
482            None
483        );
484
485        // decimal to i16
486        let decimal_array = array
487            .clone()
488            .into_iter()
489            .collect::<Decimal128Array>()
490            .with_precision_and_scale(10, 0)?;
491        generic_decimal_to_other_test_cast!(
492            decimal_array,
493            Decimal128(10, 0),
494            Int16Array,
495            Int16,
496            [
497                Some(1_i16),
498                Some(2_i16),
499                Some(3_i16),
500                Some(4_i16),
501                Some(5_i16),
502                None
503            ],
504            None
505        );
506
507        // decimal to i32
508        let decimal_array = array
509            .clone()
510            .into_iter()
511            .collect::<Decimal128Array>()
512            .with_precision_and_scale(10, 0)?;
513        generic_decimal_to_other_test_cast!(
514            decimal_array,
515            Decimal128(10, 0),
516            Int32Array,
517            Int32,
518            [
519                Some(1_i32),
520                Some(2_i32),
521                Some(3_i32),
522                Some(4_i32),
523                Some(5_i32),
524                None
525            ],
526            None
527        );
528
529        // decimal to i64
530        let decimal_array = array
531            .into_iter()
532            .collect::<Decimal128Array>()
533            .with_precision_and_scale(10, 0)?;
534        generic_decimal_to_other_test_cast!(
535            decimal_array,
536            Decimal128(10, 0),
537            Int64Array,
538            Int64,
539            [
540                Some(1_i64),
541                Some(2_i64),
542                Some(3_i64),
543                Some(4_i64),
544                Some(5_i64),
545                None
546            ],
547            None
548        );
549
550        // decimal to float32
551        let array = vec![
552            Some(1234),
553            Some(2222),
554            Some(3),
555            Some(4000),
556            Some(5000),
557            None,
558        ];
559        let decimal_array = array
560            .clone()
561            .into_iter()
562            .collect::<Decimal128Array>()
563            .with_precision_and_scale(10, 3)?;
564        generic_decimal_to_other_test_cast!(
565            decimal_array,
566            Decimal128(10, 3),
567            Float32Array,
568            Float32,
569            [
570                Some(1.234_f32),
571                Some(2.222_f32),
572                Some(0.003_f32),
573                Some(4.0_f32),
574                Some(5.0_f32),
575                None
576            ],
577            None
578        );
579
580        // decimal to float64
581        let decimal_array = array
582            .into_iter()
583            .collect::<Decimal128Array>()
584            .with_precision_and_scale(20, 6)?;
585        generic_decimal_to_other_test_cast!(
586            decimal_array,
587            Decimal128(20, 6),
588            Float64Array,
589            Float64,
590            [
591                Some(0.001234_f64),
592                Some(0.002222_f64),
593                Some(0.000003_f64),
594                Some(0.004_f64),
595                Some(0.005_f64),
596                None
597            ],
598            None
599        );
600        Ok(())
601    }
602
603    #[test]
604    fn test_cast_numeric_to_decimal() -> Result<()> {
605        // int8
606        generic_test_cast!(
607            Int8Array,
608            Int8,
609            vec![1, 2, 3, 4, 5],
610            Decimal128Array,
611            Decimal128(3, 0),
612            [Some(1), Some(2), Some(3), Some(4), Some(5)],
613            None
614        );
615
616        // int16
617        generic_test_cast!(
618            Int16Array,
619            Int16,
620            vec![1, 2, 3, 4, 5],
621            Decimal128Array,
622            Decimal128(5, 0),
623            [Some(1), Some(2), Some(3), Some(4), Some(5)],
624            None
625        );
626
627        // int32
628        generic_test_cast!(
629            Int32Array,
630            Int32,
631            vec![1, 2, 3, 4, 5],
632            Decimal128Array,
633            Decimal128(10, 0),
634            [Some(1), Some(2), Some(3), Some(4), Some(5)],
635            None
636        );
637
638        // int64
639        generic_test_cast!(
640            Int64Array,
641            Int64,
642            vec![1, 2, 3, 4, 5],
643            Decimal128Array,
644            Decimal128(20, 0),
645            [Some(1), Some(2), Some(3), Some(4), Some(5)],
646            None
647        );
648
649        // int64 to different scale
650        generic_test_cast!(
651            Int64Array,
652            Int64,
653            vec![1, 2, 3, 4, 5],
654            Decimal128Array,
655            Decimal128(20, 2),
656            [Some(100), Some(200), Some(300), Some(400), Some(500)],
657            None
658        );
659
660        // float32
661        generic_test_cast!(
662            Float32Array,
663            Float32,
664            vec![1.5, 2.5, 3.0, 1.123_456_8, 5.50],
665            Decimal128Array,
666            Decimal128(10, 2),
667            [Some(150), Some(250), Some(300), Some(112), Some(550)],
668            None
669        );
670
671        // float64
672        generic_test_cast!(
673            Float64Array,
674            Float64,
675            vec![1.5, 2.5, 3.0, 1.123_456_8, 5.50],
676            Decimal128Array,
677            Decimal128(20, 4),
678            [
679                Some(15000),
680                Some(25000),
681                Some(30000),
682                Some(11235),
683                Some(55000)
684            ],
685            None
686        );
687        Ok(())
688    }
689
690    #[test]
691    fn test_cast_i32_u32() -> Result<()> {
692        generic_test_cast!(
693            Int32Array,
694            Int32,
695            vec![1, 2, 3, 4, 5],
696            UInt32Array,
697            UInt32,
698            [
699                Some(1_u32),
700                Some(2_u32),
701                Some(3_u32),
702                Some(4_u32),
703                Some(5_u32)
704            ],
705            None
706        );
707        Ok(())
708    }
709
710    #[test]
711    fn test_cast_i32_utf8() -> Result<()> {
712        generic_test_cast!(
713            Int32Array,
714            Int32,
715            vec![1, 2, 3, 4, 5],
716            StringArray,
717            Utf8,
718            [Some("1"), Some("2"), Some("3"), Some("4"), Some("5")],
719            None
720        );
721        Ok(())
722    }
723
724    #[test]
725    fn test_cast_i64_t64() -> Result<()> {
726        let original = vec![1, 2, 3, 4, 5];
727        let expected: Vec<Option<i64>> = original
728            .iter()
729            .map(|i| Some(Time64NanosecondArray::from(vec![*i]).value(0)))
730            .collect();
731        generic_test_cast!(
732            Int64Array,
733            Int64,
734            original,
735            TimestampNanosecondArray,
736            Timestamp(TimeUnit::Nanosecond, None),
737            expected,
738            None
739        );
740        Ok(())
741    }
742
743    #[test]
744    fn invalid_cast() {
745        // Ensure a useful error happens at plan time if invalid casts are used
746        let schema = Schema::new(vec![Field::new("a", Int32, false)]);
747
748        let result = cast(
749            col("a", &schema).unwrap(),
750            &schema,
751            Interval(IntervalUnit::MonthDayNano),
752        );
753        result.expect_err("expected Invalid CAST");
754    }
755
756    #[test]
757    fn invalid_cast_with_options_error() -> Result<()> {
758        // Ensure a useful error happens at plan time if invalid casts are used
759        let schema = Schema::new(vec![Field::new("a", Utf8, false)]);
760        let a = StringArray::from(vec!["9.1"]);
761        let batch = RecordBatch::try_new(Arc::new(schema.clone()), vec![Arc::new(a)])?;
762        let expression = cast_with_options(col("a", &schema)?, &schema, Int32, None)?;
763        let result = expression.evaluate(&batch);
764
765        match result {
766            Ok(_) => panic!("expected error"),
767            Err(e) => {
768                assert!(e
769                    .to_string()
770                    .contains("Cannot cast string '9.1' to value of Int32 type"))
771            }
772        }
773        Ok(())
774    }
775
776    #[test]
777    #[ignore] // TODO: https://github.com/apache/datafusion/issues/5396
778    fn test_cast_decimal() -> Result<()> {
779        let schema = Schema::new(vec![Field::new("a", Int64, false)]);
780        let a = Int64Array::from(vec![100]);
781        let batch = RecordBatch::try_new(Arc::new(schema.clone()), vec![Arc::new(a)])?;
782        let expression =
783            cast_with_options(col("a", &schema)?, &schema, Decimal128(38, 38), None)?;
784        expression.evaluate(&batch)?;
785        Ok(())
786    }
787
788    #[test]
789    fn test_fmt_sql() -> Result<()> {
790        let schema = Schema::new(vec![Field::new("a", Int32, true)]);
791
792        // Test numeric casting
793        let expr = cast(col("a", &schema)?, &schema, Int64)?;
794        let display_string = expr.to_string();
795        assert_eq!(display_string, "CAST(a@0 AS Int64)");
796        let sql_string = fmt_sql(expr.as_ref()).to_string();
797        assert_eq!(sql_string, "CAST(a AS Int64)");
798
799        // Test string casting
800        let schema = Schema::new(vec![Field::new("b", Utf8, true)]);
801        let expr = cast(col("b", &schema)?, &schema, Int32)?;
802        let display_string = expr.to_string();
803        assert_eq!(display_string, "CAST(b@0 AS Int32)");
804        let sql_string = fmt_sql(expr.as_ref()).to_string();
805        assert_eq!(sql_string, "CAST(b AS Int32)");
806
807        Ok(())
808    }
809}
datafusion_physical_expr/expressions/cast.rs

datafusion_physical_expr/expressions/
cast.rs
