Struct PkGroup 

pub struct PkGroup<Table>(/* private fields */);

Type-level GROUP BY marker: the group key is table Table’s single-column primary key.

Produced by the proc-macro IntoGroupBy impl when .group_by(col) is called with a table’s sole primary-key column. Every other column of that table is functionally dependent on its primary key (SQL:1999), so any scalar column of Table may appear in SELECT without being listed in GROUP BY. Columns of other tables (e.g. joined tables) still must be aggregated.

Beyond correctness, grouping by the bare primary key lets the database stream groups off the PK order instead of sorting the full result through a temp structure, which matters for GROUP BY ... ORDER BY pk LIMIT n.

Trait Implementations

impl<Table: Clone> Clone for PkGroup<Table>

fn clone(&self) -> PkGroup<Table>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<Table: Copy> Copy for PkGroup<Table>

impl<Table: Debug> Debug for PkGroup<Table>

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

Formats the value using the given formatter.

impl<Table: Default> Default for PkGroup<Table>

fn default() -> PkGroup<Table>

Returns the “default value” for a type.

impl<Scope, Cols, T, Proof> MarkerAggValidFor<PkGroup<T>, Proof> for Scoped<SelectCols<Cols>, Scope>

where Cols: ScalarColumnsIn<PkGroup<T>, Proof>,

impl<Scope, T> MarkerAggValidFor<PkGroup<T>> for Scoped<SelectStar, Scope>

impl<Scope, T> MarkerAggValidFor<PkGroup<T>> for Scoped<SelectExpr, Scope>

impl<Scope, R, T> MarkerAggValidFor<PkGroup<T>> for Scoped<SelectAs<R>, Scope>