Type Alias diesel::dsl::exists

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pub type exists<Expr> = Exists<Expr>;
Expand description

The return type of exists(expr)

Aliased Type§

struct exists<Expr> {
    pub subselect: Subselect<Expr, Bool>,
}

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§subselect: Subselect<Expr, Bool>

The inner subselect

Trait Implementations§

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impl<T: Clone> Clone for Exists<T>

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fn clone(&self) -> Exists<T>

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl<T: Debug> Debug for Exists<T>

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

Formats the value using the given formatter. Read more
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impl<T> Expression for Exists<T>where Subselect<T, Bool>: Expression,

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type SqlType = Bool

The type that this expression represents in SQL
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impl<T, DB> QueryFragment<DB, AnsiSqlExistsSyntax> for Exists<T>where DB: Backend + SqlDialect<ExistsSyntax = AnsiSqlExistsSyntax>, T: QueryFragment<DB>,

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

Walk over this QueryFragment for all passes. Read more
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fn to_sql(&self, out: &mut DB::QueryBuilder, backend: &DB) -> QueryResult<()>

Converts this QueryFragment to its SQL representation. Read more
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fn collect_binds<'b>( &'b self, out: &mut <DB as HasBindCollector<'b>>::BindCollector, metadata_lookup: &mut DB::MetadataLookup, backend: &'b DB ) -> QueryResult<()>

Serializes all bind parameters in this query. Read more
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fn is_safe_to_cache_prepared(&self, backend: &DB) -> QueryResult<bool>

Is this query safe to store in the prepared statement cache? Read more
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fn is_noop(&self, backend: &DB) -> QueryResult<bool>

Does walking this AST have any effect?
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impl<T: QueryId> QueryId for Exists<T>

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type QueryId = Exists<<T as QueryId>::QueryId>

A type which uniquely represents Self in a SQL query. Read more
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const HAS_STATIC_QUERY_ID: bool = _

Can the SQL generated by Self be uniquely identified by its type? Read more
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fn query_id() -> Option<TypeId>

Returns the type id of Self::QueryId if Self::HAS_STATIC_QUERY_ID. Returns None otherwise. Read more
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impl<T, GB> ValidGrouping<GB> for Exists<T>where Subselect<T, Bool>: ValidGrouping<GB>,

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type IsAggregate = <Subselect<T, Bool> as ValidGrouping<GB>>::IsAggregate

Is this expression aggregate? Read more
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impl<T, QS> AppearsOnTable<QS> for Exists<T>where Self: Expression, Subselect<T, Bool>: AppearsOnTable<QS>,

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impl<T: Copy> Copy for Exists<T>

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impl<T, QS> SelectableExpression<QS> for Exists<T>where Self: AppearsOnTable<QS>, Subselect<T, Bool>: SelectableExpression<QS>,