Enum Aggregate 

pub enum Aggregate {
    Count,
    Sum(Box<str>),
    Avg(Box<str>),
}

An aggregate over a (correlated) subquery’s rows (REDUCE-DESIGN.md).

Set on a Ast that is a related subquery, it marks that relationship as a relationship aggregate — issue { commentCount: count(comments) } — which the builder (08) lowers to a grouped reduce + a scalar-projected singular relationship (§9) instead of a row-materializing join. Set on the root Ast, it is a top-level aggregate (SELECT count(*) FROM …, optionally with group_by/having).

Sum/Avg carry the column name they aggregate (resolved to a child/source ColId by the builder). All three are invertible, so reduce maintains them from a pure delta stream. Serde is externally tagged: Count ⇒ the bare string "count"; Sum(c) ⇒ {"sum": c}; Avg(c) ⇒ {"avg": c}.

Variants

Count

count(*) over the subquery’s (filtered) rows.

Sum(Box<str>)

sum(col) over the subquery’s (filtered) rows — Σ of the non-NULL values.

Avg(Box<str>)

avg(col) over the subquery’s (filtered) rows — sum / count of the non-NULL values (NULL when there are none).

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<'de> Deserialize<'de> for Aggregate

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

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 Serialize for Aggregate

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Eq for Aggregate

impl StructuralPartialEq for Aggregate