Struct Merge 

pub struct Merge<X: Extension = NoExt> {
    pub with: Option<With<X>>,
    pub target: DmlTarget,
    pub using: TableWithJoins<X>,
    pub on: Expr<X>,
    pub clauses: ThinVec<MergeWhenClause<X>>,
    pub returning: Option<Returning<X>>,
    pub meta: Meta,
}

MERGE INTO <target> [AS alias] USING <source> ON <condition> <when_clause>+ statement (SQL:2003 feature F312; the standard upsert).

One canonical shape: the standard models MERGE directly, so this is a shared node gated for acceptance by MutationSyntax::merge — on in ANSI (SQL:2016) and PostgreSQL 15+, off in MySQL — never a dialect fork. The clause reuses the existing mutation shapes rather than parallel ones: the MERGE INTO <target> relation is the shared DmlTarget (carrying the same ONLY/* inheritance marker UPDATE/DELETE targets do), the USING source is a TableWithJoins (SQL:2016’s <table reference> — a table, a derived subquery, or a joined table, exactly as in a FROM clause), and the WHEN actions reuse the INSERT value element (InsertValue) and the UPDATE ... SET assignment list (UpdateAssignment).

Boxed at the Statement seam (Statement::Merge) because MERGE is a fat, infrequent variant — its when_clause list and the embedded source and condition make it one of the widest statements — so boxing keeps the common Statement lean.

Fields

with: Option<With<X>>

Optional statement-level WITH clause (WITH ... MERGE INTO ...; PostgreSQL 15+ and DuckDB, probed on 1.5.4). Not standard surface — SQL:2016’s <merge statement> takes no WITH — so it is gated by MutationSyntax::cte_before_merge, the MERGE counterpart of Insert::with’s cte_before_insert gate.

target: DmlTarget

MERGE INTO <target> — the table rows are merged into, plus its optional correlation alias and PostgreSQL ONLY/* inheritance marker. Reuses the shared DmlTarget shape (UPDATE/DELETE use the same one), so MERGE INTO ONLY t and MERGE INTO t * ride the same table_expressions.only gate as those statements — never a parallel target type.

using: TableWithJoins<X>

USING <source> — the data source the target is merged against: a table, a derived subquery, or a joined table, reusing the TableWithJoins shape (a relation plus its chained joins, exactly as a FROM item; SQL:2016’s USING <table reference>) rather than a parallel source type. A bare comma-separated list is not admitted — the merge source is one <table reference>, so USING a, b rejects (engine-verified on pg_query 17).

on: Expr<X>

The ON <join predicate> matching condition.

clauses: ThinVec<MergeWhenClause<X>>

WHEN [NOT] MATCHED ... clauses, in source order. The parser guarantees at least one; the standard requires a non-empty list.

returning: Option<Returning<X>>

RETURNING ... output clause (PostgreSQL 17+ and DuckDB, probed on 1.5.4; where merge_action() is also admitted as an output expression). Rides the same MutationSyntax::returning gate as the other DML statements — every shipped dialect with merge on either accepts both or rejects both.

meta: Meta

Source location and node identity.

Trait Implementations

impl<X: Clone + Extension> Clone for Merge<X>

fn clone(&self) -> Merge<X>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<X: Debug + Extension> Debug for Merge<X>

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

Formats the value using the given formatter.

impl<'de, X> Deserialize<'de> for Merge<X>

where X: Deserialize<'de> + Extension,

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<X: Eq + Extension> Eq for Merge<X>

impl<X: Hash + Extension> Hash for Merge<X>

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<X: PartialEq + Extension> PartialEq for Merge<X>

fn eq(&self, other: &Merge<X>) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl<X: Extension + Render> Render for Merge<X>

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

Return the render for this value.

fn operand_binding_power(&self) -> Option<BindingPower>

The binding power this node contributes when it appears as an operand, or None (the default) for a self-delimiting node — an atom, call, or constructor — that never needs parentheses.

impl<X> Serialize for Merge<X>

where X: Serialize + Extension,

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl<X: Extension> Spanned for Merge<X>

fn span(&self) -> Span

Return the span for this value.

impl<X: PartialEq + Extension> StructuralPartialEq for Merge<X>