Struct Aggregate 

#[non_exhaustive]
pub struct Aggregate {
    pub input: Arc<LogicalPlan>,
    pub group_expr: Vec<Expr>,
    pub aggr_expr: Vec<Expr>,
    pub schema: DFSchemaRef,
}

Aggregates its input based on a set of grouping and aggregate expressions (e.g. SUM).

Output Schema

The output schema is the group expressions followed by the aggregate expressions in order.

For example, given the input schema "A", "B", "C" and the aggregate SUM(A) GROUP BY C+B, the output schema will be "C+B", "SUM(A)" where “C+B” and “SUM(A)” are the names of the output columns. Note that “C+B” is a single new column

Fields (Non-exhaustive)

Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.

input: Arc<LogicalPlan>

The incoming logical plan

group_expr: Vec<Expr>

Grouping expressions

aggr_expr: Vec<Expr>

Aggregate expressions.

Note these must be either Expr::AggregateFunction or Expr::Alias

schema: DFSchemaRef

The schema description of the aggregate output

Implementations

impl Aggregate

pub const INTERNAL_GROUPING_ID: &'static str = "__grouping_id"

Internal column used when the aggregation is a grouping set.

This column packs two values into a single unsigned integer:

• Low bits (positions 0 .. n-1): a semantic bitmask where each bit represents one of the n grouping expressions. The least significant bit corresponds to the rightmost grouping expression. A 1 bit means the corresponding column is replaced with NULL for this grouping set; a 0 bit means it is included.
• High bits (positions n and above): a duplicate ordinal that distinguishes multiple occurrences of the same semantic grouping set pattern within a single query. The ordinal is 0 for the first occurrence, 1 for the second, and so on.

The integer type is chosen by Self::grouping_id_type to be the smallest UInt8 / UInt16 / UInt32 / UInt64 that can represent both parts.

For example, for the grouping expressions CUBE(a, b) (no duplicates), the grouping ID column will have the following values: 0b00: Both a and b are included 0b01: b is excluded 0b10: a is excluded 0b11: Both a and b are excluded

When the same set appears twice and n = 2, the duplicate ordinal is packed into bit 2: first occurrence: 0b0_01 (ordinal = 0, mask = 0b01) second occurrence: 0b1_01 (ordinal = 1, mask = 0b01)

The GROUPING function always masks the value with (1 << n) - 1 before interpreting it so the ordinal bits are invisible to user-facing SQL.

pub fn try_new( input: Arc<LogicalPlan>, group_expr: Vec<Expr>, aggr_expr: Vec<Expr>, ) -> Result<Self>

Create a new aggregate operator.

pub fn try_new_with_schema( input: Arc<LogicalPlan>, group_expr: Vec<Expr>, aggr_expr: Vec<Expr>, schema: DFSchemaRef, ) -> Result<Self>

Create a new aggregate operator using the provided schema to avoid the overhead of building the schema again when the schema is already known.

This method should only be called when you are absolutely sure that the schema being provided is correct for the aggregate. If in doubt, call try_new instead.

pub fn group_expr_len(&self) -> Result<usize>

Get the length of the group by expression in the output schema This is not simply group by expression length. Expression may be GroupingSet, etc. In these case we need to get inner expression lengths.

pub fn grouping_id_type(group_exprs: usize, max_ordinal: usize) -> DataType

Returns the data type of the grouping id.

The grouping ID packs two pieces of information into a single integer:

• The low group_exprs bits are the semantic bitmask (a set bit means the corresponding grouping expression is NULL for this grouping set).
• The bits above position group_exprs encode a duplicate ordinal that distinguishes multiple occurrences of the same grouping set pattern.

max_ordinal is the highest ordinal value that will appear (0 when there are no duplicate grouping sets). The type is chosen to be the smallest unsigned integer that can represent both parts.

Trait Implementations

impl Clone for Aggregate

fn clone(&self) -> Aggregate

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Aggregate

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for Aggregate

impl Hash for Aggregate

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for Aggregate

fn eq(&self, other: &Aggregate) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for Aggregate

fn partial_cmp(&self, other: &Self) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl StructuralPartialEq for Aggregate