Enum Item 

pub enum Item {
    All(Option<String>),
    Column(Name, Option<String>),
    Count(Option<String>),
    Aggregate(Agg, Name, Option<String>),
    Literal(Datum, Option<String>),
    Expr(Expr, Option<String>),
}

Variants

All(Option<String>)

*, or t.*.

Column(Name, Option<String>)

Count(Option<String>)

Aggregate(Agg, Name, Option<String>)

min(c), max(c) or sum(c) — the three aggregates whose answer depends on what the rows say. crate::plan::Op::GroupBy is what maintains each, and count is not one of them because a count needs nothing of the row at all.

Literal(Datum, Option<String>)

Expr(Expr, Option<String>)

Anything else a select list can hold — a case, a call, a comparison, a cast.

Separate from Item::Column and Item::Literal rather than subsuming them, because those two are what crate::query compiles into the plan for a group by and a distinct: an expression there would be an expression inside an operator, and this evaluates them over the rows an operator produced.

Implementations

impl Item

pub fn aggregates(&self) -> bool

Whether this item is an aggregate, which is what decides that a query groups.

Trait Implementations

impl Clone for Item

fn clone(&self) -> Item

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Item

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

Formats the value using the given formatter.