Module datafusion::prelude

Expand description

A “prelude” for users of the datafusion crate.

Like the standard library’s prelude, this module simplifies importing of common items. Unlike the standard prelude, the contents of this module must be imported manually:

use datafusion::prelude::*;

Re-exports

pub use crate::dataframe::DataFrame;

pub use crate::execution::context::SessionConfig;

pub use crate::execution::context::SessionContext;

pub use crate::execution::options::AvroReadOptions;

pub use crate::execution::options::CsvReadOptions;

pub use crate::execution::options::NdJsonReadOptions;

pub use crate::execution::options::ParquetReadOptions;

Structs

Column

A named reference to a qualified field in a schema.

Enums

Expr

Expr is a central struct of DataFusion’s query API, and represent logical expressions such as A + 1, or CAST(c1 AS int).

JoinType

Join type

Partitioning

Logical partitioning schemes supported by the repartition operator.

Functions

approx_percentile_cont

Calculate an approximation of the specified percentile for expr.

array

Returns an array of fixed size with each argument on it.

ascii

Scalar function definition for ascii

avg

Create an expression to represent the avg() aggregate function

bit_length

Scalar function definition for bit_length

btrim

Scalar function definition for btrim

cast

Create a cast expression

character_length

Scalar function definition for character_length

chr

Scalar function definition for chr

coalesce

Returns coalesce(args...), which evaluates to the value of the first Expr which is not NULL

col

Create a column expression based on a qualified or unqualified column name

concat

Concatenates the text representations of all the arguments. NULL arguments are ignored.

concat_ws

Concatenates all but the first argument, with separators. The first argument is used as the separator string, and should not be NULL. Other NULL arguments are ignored.

count

Create an expression to represent the count() aggregate function

create_udf

Creates a new UDF with a specific signature and specific return type. This is a helper function to create a new UDF. The function create_udf returns a subset of all possible ScalarFunction:

date_part

Scalar function definition for date_part

date_trunc

Scalar function definition for date_trunc

digest

Scalar function definition for digest

exists

Create an EXISTS subquery expression

from_unixtime

Scalar function definition for from_unixtime

in_list

Create an in_list expression