Struct Distinct 

pub struct Distinct {
    pub on: Vec<Expr>,
}

SELECT DISTINCT or SELECT DISTINCT ON (a, b).

From PostgreSQL 17: SELECT [ ALL | DISTINCT [ ON ( expression [, ...] ) ] ]. ALL is the default and adds nothing, so it is not representable; the absence of a Distinct is what ALL means.

A SelectQuery stores this as an Option, because DISTINCT with an empty ON list is a different statement from no DISTINCT at all — which is exactly the distinction bob loses by keying off On != nil.

Fields

on: Vec<Expr>

The ON expressions. Empty is a plain DISTINCT.

Trait Implementations

impl Clone for Distinct

fn clone(&self) -> Distinct

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Distinct

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

Formats the value using the given formatter.

impl Default for Distinct

fn default() -> Distinct

Returns the “default value” for a type.

impl Expression for Distinct

fn write_sql(&self, w: &mut SqlWriter<'_>)

Append this fragment to w.