Crate datafusion_expr
source · [−]Re-exports
Modules
Expr module contains core type definition for Expr.
Expr fn module contains the functional definitions for expressions.
Structs
Logical representation of a user-defined aggregate function (UDAF) A UDAF is different from a UDF in that it is stateful across batches.
Logical representation of a UDF.
The Signature of a function defines its supported input types as well as its volatility.
The frame-spec determines which output rows are read by an aggregate window function.
Enums
Enum of all built-in aggregate functions
An aggregate function that is part of a built-in window function
Enum of all built-in scalar functions
Represents the result from an expression
Operators applied to expressions
A function’s type signature, which defines the function’s supported argument types.
A function’s volatility, which defines the functions eligibility for certain optimizations
There are five ways to describe starting and ending frame boundaries:
There are three frame types: ROWS, GROUPS, and RANGE. The frame type determines how the starting and ending boundaries of the frame are measured.
WindowFunction
Traits
An accumulator represents a stateful object that lives throughout the evaluation of multiple rows and generically accumulates values.
Trait for converting a type to a literal timestamp
Functions
Create a literal expression
Create a literal timestamp expression
Type Definitions
the implementation of an aggregate function
null columnar values are implemented as a null array in order to pass batch num_rows
A function’s return type
Scalar function
This signature corresponds to which types an aggregator serializes its state, given its return datatype.