Jefffrey commented on code in PR #19311: URL: https://github.com/apache/datafusion/pull/19311#discussion_r2653227401
########## datafusion/optimizer/src/simplify_expressions/simplify_sql_literal.rs: ########## @@ -0,0 +1,232 @@ +// 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. + +//! Parses and simplifies a SQL expression to a literal of a given type. Review Comment: Here too ########## datafusion/optimizer/src/simplify_expressions/simplify_sql_literal.rs: ########## @@ -0,0 +1,232 @@ +// 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. + +//! Parses and simplifies a SQL expression to a literal of a given type. +//! +//! This module provides functionality to parse and simplify static SQL expressions +//! used in SQL constructs like `FROM TABLE SAMPLE (10 + 50 * 2)`. If they are required +//! in a planning (not an execution) phase, they need to be reduced to literals of a given type. + +use crate::simplify_expressions::ExprSimplifier; +use arrow::datatypes::ArrowPrimitiveType; +use datafusion_common::{ + DFSchema, DFSchemaRef, DataFusionError, Result, ScalarValue, plan_datafusion_err, + plan_err, +}; +use datafusion_expr::Expr; +use datafusion_expr::execution_props::ExecutionProps; +use datafusion_expr::simplify::SimplifyContext; +use std::sync::Arc; + +/// Parse and simplifies a SQL expression to a numeric literal, +/// corresponding to an arrow primitive type `T` (for example, Float64Type). +/// +/// This function simplifies and coerces the expression, then extracts the underlying +/// native type using `TryFrom<ScalarValue>`. +/// +/// # Example +/// ```ignore +/// let value: f64 = parse_sql_literal::<Float64Type>(expr)?; +/// ``` +pub fn parse_sql_literal<T>(expr: &Expr) -> Result<T::Native> +where + T: ArrowPrimitiveType, + T::Native: TryFrom<ScalarValue, Error = DataFusionError>, +{ + // Empty schema is sufficient because it parses only literal expressions + let schema = DFSchemaRef::new(DFSchema::empty()); + + log::debug!("Parsing expr {:?} to type {}", expr, T::DATA_TYPE); + + let execution_props = ExecutionProps::new(); + let simplifier = ExprSimplifier::new( + SimplifyContext::new(&execution_props).with_schema(Arc::clone(&schema)), + ); + + // Simplify and coerce expression in case of constant arithmetic operations (e.g., 10 + 5) + let simplified_expr: Expr = simplifier + .simplify(expr.clone()) + .map_err(|err| plan_datafusion_err!("Cannot simplify {expr:?}: {err}"))?; + let coerced_expr: Expr = simplifier.coerce(simplified_expr, schema.as_ref())?; + log::debug!("Coerced expression: {:?}", &coerced_expr); + + match coerced_expr { + Expr::Literal(scalar_value, _) => { + // It is a literal - proceed to the underlying value + // Cast to the target type if needed + let casted_scalar = scalar_value.cast_to(&T::DATA_TYPE)?; + + // Extract the native type + T::Native::try_from(casted_scalar).map_err(|err| { + plan_datafusion_err!( + "Cannot extract {} from scalar value: {err}", + std::any::type_name::<T>() + ) + }) + } + actual => { + plan_err!( + "Cannot extract literal from coerced {actual:?} expression given {expr:?} expression" + ) + } + } +} + +#[cfg(test)] +mod tests { + use super::*; + use arrow::datatypes::{DataType, Float64Type, Int64Type}; + use datafusion_common::config::ConfigOptions; + use datafusion_common::{TableReference, not_impl_err}; + use datafusion_expr::planner::{ContextProvider, RelationPlannerContext}; + use datafusion_expr::sqlparser::parser::Parser; + use datafusion_expr::{AggregateUDF, ScalarUDF, TableSource, WindowUDF}; + use datafusion_sql::planner::{PlannerContext, SqlToRel}; + use datafusion_sql::relation::SqlToRelRelationContext; + use datafusion_sql::sqlparser::dialect::GenericDialect; + use std::sync::Arc; + + // Simple mock context provider for testing + struct MockContextProvider { Review Comment: These tests can probably be simplified to remove the SQL parsing related code and only supply Expr to test cases ########## datafusion/optimizer/src/simplify_expressions/simplify_sql_literal.rs: ########## @@ -0,0 +1,232 @@ +// 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. + +//! Parses and simplifies a SQL expression to a literal of a given type. +//! +//! This module provides functionality to parse and simplify static SQL expressions +//! used in SQL constructs like `FROM TABLE SAMPLE (10 + 50 * 2)`. If they are required +//! in a planning (not an execution) phase, they need to be reduced to literals of a given type. + +use crate::simplify_expressions::ExprSimplifier; +use arrow::datatypes::ArrowPrimitiveType; +use datafusion_common::{ + DFSchema, DFSchemaRef, DataFusionError, Result, ScalarValue, plan_datafusion_err, + plan_err, +}; +use datafusion_expr::Expr; +use datafusion_expr::execution_props::ExecutionProps; +use datafusion_expr::simplify::SimplifyContext; +use std::sync::Arc; + +/// Parse and simplifies a SQL expression to a numeric literal, +/// corresponding to an arrow primitive type `T` (for example, Float64Type). +/// +/// This function simplifies and coerces the expression, then extracts the underlying +/// native type using `TryFrom<ScalarValue>`. +/// +/// # Example +/// ```ignore +/// let value: f64 = parse_sql_literal::<Float64Type>(expr)?; +/// ``` +pub fn parse_sql_literal<T>(expr: &Expr) -> Result<T::Native> Review Comment: We just need to fix the documentation and rename this to omit mention of SQL now, since it only operates at Expr level -- This is an automated message from the Apache Git Service. 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