Struct SampleClause 

pub struct SampleClause {
    pub method: Option<ObjectName>,
    pub size: Literal,
    pub unit: SampleUnit,
    pub seed: Option<Literal>,
    pub meta: Meta,
}

DuckDB’s USING SAMPLE <entry> query-level sample specification (its tablesample_entry grammar).

DuckDB admits two surface shapes for the entry that are semantically identical, so they fold to this one canonical shape (the renderer re-derives a method-first spelling): a count-first <size> [unit] [ '(' method [',' seed] ')' ] (USING SAMPLE 3, USING SAMPLE 50% (bernoulli)) and a method-first method '(' <size> [unit] ')' [REPEATABLE '(' seed ')'] (USING SAMPLE reservoir(20 PERCENT) REPEATABLE (42)). The size and seed are always numeric literals (DuckDB rejects a negative or general-expression size), so the node carries no expression and is not generic over X.

Fields

method: Option<ObjectName>

The sampling method (reservoir/bernoulli/system), or None for the bare count form (USING SAMPLE 3). Whether the method led or trailed the count in source is not preserved — the two orders are equivalent and render method-first.

size: Literal

The sample size literal (3, 50, 3.5).

unit: SampleUnit

The size unit: a bare count, an explicit ROWS, or a percentage (PERCENT keyword or the % sign).

seed: Option<Literal>

The random seed from REPEATABLE (seed) or the inline (method, seed) form; None when unwritten.

meta: Meta

Source location and node identity.

Trait Implementations

impl Clone for SampleClause

fn clone(&self) -> SampleClause

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for SampleClause

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for SampleClause

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Eq for SampleClause

impl Hash for SampleClause

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 PartialEq for SampleClause

fn eq(&self, other: &SampleClause) -> bool

Equality operator ==.

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

Inequality operator !=.

impl Render for SampleClause

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 Serialize for SampleClause

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

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Spanned for SampleClause

fn span(&self) -> Span

Return the span for this value.

impl StructuralPartialEq for SampleClause