diesel::query_builder

Struct Distinct

pub struct Distinct;

Available on crate feature i-implement-a-third-party-backend-and-opt-into-breaking-changes only.

Expand description

Remove duplicate rows in the result, this is the default behavior of UNION, INTERSECT and EXCEPT

Trait Implementations§

impl Clone for Distinct

fn clone(&self) -> Distinct

Returns a copy of the value. Read more

1.0.0 · Source§

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

Performs copy-assignment from source. Read more

impl Debug for Distinct

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

Formats the value using the given formatter. Read more

impl<DB> QueryFragment<DB> for Distinct
where DB: Backend + DieselReserveSpecialization,

fn walk_ast<'b>(&'b self, _: AstPass<'_, 'b, DB>) -> QueryResult<()>

Walk over this QueryFragment for all passes. Read more

fn to_sql(&self, out: &mut DB::QueryBuilder, backend: &DB) -> QueryResult<()>

Available on crate feature i-implement-a-third-party-backend-and-opt-into-breaking-changes only.

Converts this QueryFragment to its SQL representation. Read more

fn collect_binds<'b>( &'b self, out: &mut DB::BindCollector<'b>, metadata_lookup: &mut DB::MetadataLookup, backend: &'b DB, ) -> QueryResult<()>

Available on crate feature i-implement-a-third-party-backend-and-opt-into-breaking-changes only.

Serializes all bind parameters in this query. Read more

fn is_safe_to_cache_prepared(&self, backend: &DB) -> QueryResult<bool>

Available on crate feature i-implement-a-third-party-backend-and-opt-into-breaking-changes only.

Is this query safe to store in the prepared statement cache? Read more

fn is_noop(&self, backend: &DB) -> QueryResult<bool>

Available on crate feature i-implement-a-third-party-backend-and-opt-into-breaking-changes only.

Does walking this AST have any effect?

impl QueryId for Distinct

const HAS_STATIC_QUERY_ID: bool = true

Can the SQL generated by Self be uniquely identified by its type? Read more

type QueryId = Distinct

A type which uniquely represents Self in a SQL query. Read more

fn query_id() -> Option<TypeId>

Returns the type id of Self::QueryId if Self::HAS_STATIC_QUERY_ID. Returns None otherwise. Read more

impl Copy for Distinct

impl SupportsCombinationClause<Except, Distinct> for Pg

Available on crate feature postgres_backend only.

impl SupportsCombinationClause<Except, Distinct> for Sqlite

Available on crate feature sqlite only.

impl SupportsCombinationClause<Intersect, Distinct> for Pg

Available on crate feature postgres_backend only.

impl SupportsCombinationClause<Intersect, Distinct> for Sqlite

Available on crate feature sqlite only.

impl SupportsCombinationClause<Union, Distinct> for Mysql

Available on crate feature mysql_backend only.

impl SupportsCombinationClause<Union, Distinct> for Pg

Available on crate feature postgres_backend only.

impl SupportsCombinationClause<Union, Distinct> for Sqlite

Available on crate feature sqlite only.

Auto Trait Implementations§

impl Freeze for Distinct

impl RefUnwindSafe for Distinct

impl Send for Distinct

impl Sync for Distinct

impl Unpin for Distinct

impl UnwindSafe for Distinct

Blanket Implementations§

impl<T> Any for T
where T: 'static + ?Sized,

fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more

impl<T> Borrow<T> for T
where T: ?Sized,

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more

impl<T> BorrowMut<T> for T
where T: ?Sized,

fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more

impl<T> CloneToUninit for T
where T: Clone,

unsafe fn clone_to_uninit(&self, dst: *mut u8)

🔬This is a nightly-only experimental API. (clone_to_uninit)

Performs copy-assignment from self to dst. Read more

impl<T> Downcast for T
where T: Any,

fn into_any(self: Box<T>) -> Box<dyn Any>

Convert Box<dyn Trait> (where Trait: Downcast) to Box<dyn Any>. Box<dyn Any> can then be further downcast into Box<ConcreteType> where ConcreteType implements Trait.

fn into_any_rc(self: Rc<T>) -> Rc<dyn Any>

Convert Rc<Trait> (where Trait: Downcast) to Rc<Any>. Rc<Any> can then be further downcast into Rc<ConcreteType> where ConcreteType implements Trait.

fn as_any(&self) -> &(dyn Any + 'static)

Convert &Trait (where Trait: Downcast) to &Any. This is needed since Rust cannot generate &Any’s vtable from &Trait’s.

fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)

Convert &mut Trait (where Trait: Downcast) to &Any. This is needed since Rust cannot generate &mut Any’s vtable from &mut Trait’s.

impl<T> DowncastSync for T
where T: Any + Send + Sync,

fn into_any_arc(self: Arc<T>) -> Arc<dyn Any + Send + Sync>

Convert Arc<Trait> (where Trait: Downcast) to Arc<Any>. Arc<Any> can then be further downcast into Arc<ConcreteType> where ConcreteType implements Trait.

impl<Conn, DB, T> ExecuteDsl<Conn, DB> for T
where Conn: Connection<Backend = DB>, DB: Backend, T: QueryFragment<DB> + QueryId,

fn execute(query: T, conn: &mut Conn) -> Result<usize, Error>

Execute this command

impl<T> From<T> for T

fn from(t: T) -> T

Returns the argument unchanged.

impl<T, U> Into<U> for T
where U: From<T>,

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

impl<T> IntoSql for T

fn into_sql<T>(self) -> AsExprOf<Self, T>
where Self: AsExpression<T> + Sized, T: SqlType + TypedExpressionType,

Convert self to an expression for Diesel’s query builder. Read more

fn as_sql<'a, T>(&'a self) -> AsExprOf<&'a Self, T>
where &'a Self: AsExpression<T>, T: SqlType + TypedExpressionType,

Convert &self to an expression for Diesel’s query builder. Read more

impl<T, DB> QueryFragmentForCachedStatement<DB> for T
where DB: Backend, <DB as Backend>::QueryBuilder: Default, T: QueryFragment<DB>,

fn construct_sql(&self, backend: &DB) -> Result<String, Error>

Available on crate feature i-implement-a-third-party-backend-and-opt-into-breaking-changes only.

Convert the query fragment into a SQL string for the given backend

fn is_safe_to_cache_prepared(&self, backend: &DB) -> Result<bool, Error>

Available on crate feature i-implement-a-third-party-backend-and-opt-into-breaking-changes only.

Check whether it’s safe to cache the query

impl<T> ToOwned for T
where T: Clone,

type Owned = T

The resulting type after obtaining ownership.

fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more

fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more

impl<T, U> TryFrom<U> for T
where U: Into<T>,

type Error = Infallible

The type returned in the event of a conversion error.

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.

impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.

fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.

impl<V, T> VZip<V> for T
where V: MultiLane<T>,

fn vzip(self) -> V

impl<T> ErasedDestructor for T
where T: 'static,

impl<T> MaybeSendSync for T