Crate datafusion_expr

DataFusion is an extensible query execution framework that uses Apache Arrow as its in-memory format.

This crate is a submodule of DataFusion that provides types representing logical query plans (LogicalPlan) and logical expressions (Expr) as well as utilities for working with these types.

The expr_fn module contains functions for creating expressions.

Re-exports

• pub use expr::Between;
• pub use expr::BinaryExpr;
• pub use expr::Case;
• pub use expr::Cast;
• pub use expr::Expr;
• pub use expr::GetFieldAccess;
• pub use expr::GroupingSet;
• pub use expr::Like;
• pub use expr::Sort as SortExpr;
• pub use expr::TryCast;
• pub use expr::WindowFunctionDefinition;
• pub use expr_schema::ExprSchemable;
• pub use function::PartitionEvaluatorFactory;
• pub use function::ReturnTypeFunction;
• pub use function::ScalarFunctionImplementation;
• pub use function::StateTypeFunction;
• pub use window_frame::WindowFrame;
• pub use window_frame::WindowFrameBound;
• pub use window_frame::WindowFrameUnits;
• pub use sqlparser;
• pub use expr_fn::*;
• pub use logical_plan::*;

Modules

• aggregate_doc_sections
• binary
  Coercion rules for matching argument types for binary operators
• conditional_expressions
  Conditional expressions
• execution_props
• expr
  Logical Expressions: Expr
• expr_fn
  Functions for creating logical expressions
• expr_rewriter
  Expression rewriter
• expr_schema
• function
  Function module contains typing and signature for built-in and user defined functions.
• groups_accumulator
• interval_arithmetic
• logical_plan
• planner
  ContextProvider and ExprPlanner APIs to customize SQL query planning
• registry
  FunctionRegistry trait
• scalar_doc_sections
• simplify
  Structs and traits to provide the information needed for expression simplification.
• sort_properties
• test
• tree_node
  Tree node implementation for Logical Expressions
• type_coercion
  Type coercion rules for DataFusion
• utils
  Expression utilities
• var_provider
  Variable provider
• window_doc_sections
• window_frame
  Window frame module
• window_function
• window_state
  Structures used to hold window function state (for implementing WindowUDFs)

Macros

• expr_vec_fmt

Structs

• AggregateUDF
  Logical representation of a user-defined aggregate function (UDAF).
• DocSection
• Documentation
  Documentation for use by ScalarUDFImpl, AggregateUDFImpl and WindowUDFImpl functions that will be used to generate public documentation.
• DocumentationBuilder
  A builder to be used for building Documentation’s.
• ScalarUDF
  Logical representation of a Scalar User Defined Function.
• Signature
  Defines the supported argument types (TypeSignature) and Volatility for a function.
• StatisticsArgs
  Arguments passed to AggregateUDFImpl::value_from_stats
• WindowUDF
  Logical representation of a user-defined window function (UDWF) A UDWF is different from a UDF in that it is stateful across batches.

Enums

• ArrayFunctionSignature
• BuiltInWindowFunction
  A window function built in to DataFusion
• ColumnarValue
  The result of evaluating an expression.
• EmitTo
  Describes how many rows should be emitted during grouping.
• Operator
  Operators applied to expressions
• ReversedUDAF
• ReversedUDWF
• TableProviderFilterPushDown
  Indicates how a filter expression is handled by TableProvider::scan.
• TableType
  Indicates the type of this table for metadata/catalog purposes.
• TypeSignature
  A function’s type signature defines the types of arguments the function supports.
• Volatility
  A function’s volatility, which defines the functions eligibility for certain optimizations

Constants

• TIMEZONE_WILDCARD
  Constant that is used as a placeholder for any valid timezone. This is used where a function can accept a timestamp type with any valid timezone, it exists to avoid the need to enumerate all possible timezones. See TypeSignature for more details.

Traits

• Accumulator
  Tracks an aggregate function’s state.
• AggregateUDFImpl
  Trait for implementing AggregateUDF.
• GroupsAccumulator
  GroupsAccumulator implements a single aggregate (e.g. AVG) and stores the state for all groups internally.
• Literal
  Trait for converting a type to a Literal literal expression.
• PartitionEvaluator
  Partition evaluator for Window Functions
• ScalarUDFImpl
  Trait for implementing ScalarUDF.
• TableSource
  Access schema information and filter push-down capabilities.
• TimestampLiteral
  Trait for converting a type to a literal timestamp
• WindowUDFImpl
  Trait for implementing WindowUDF.

Functions

• lit
  Create a literal expression
• lit_timestamp_nano
  Create a literal timestamp expression

Type Aliases

• AccumulatorFactoryFunction
  Factory that returns an accumulator for the given aggregate function.