Enum Expr 

pub enum Expr {
    Star,
    QualifiedStar(String),
    Default,
    Column(String),
    QualifiedColumn {
        qualifier: String,
        column: String,
    },
    Literal(Value),
    Param(usize),
    Func {
        name: String,
        binding: Option<FunctionBinding>,
        args: Vec<Expr>,
        distinct: bool,
        order_by: Vec<OrderBy>,
        filter: Option<Box<Expr>>,
    },
    Array(Vec<Expr>),
    Row(Vec<Expr>),
    Binary {
        op: BinaryOp,
        lhs: Box<Expr>,
        rhs: Box<Expr>,
    },
    UnaryMinus(Box<Expr>),
    Not(Box<Expr>),
    And(Vec<Expr>),
    Or(Vec<Expr>),
    IsNull {
        expr: Box<Expr>,
        negated: bool,
    },
    Between {
        expr: Box<Expr>,
        low: Box<Expr>,
        high: Box<Expr>,
    },
    InList {
        expr: Box<Expr>,
        list: Vec<Expr>,
        negated: bool,
    },
    WindowCall {
        name: String,
        args: Vec<Expr>,
        spec: WindowSpec,
    },
    Case {
        base: Option<Box<Expr>>,
        when: Vec<(Expr, Expr)>,
        else_branch: Option<Box<Expr>>,
    },
    Cast {
        expr: Box<Expr>,
        ty: String,
    },
    ScalarSubquery(Box<SelectStmt>),
    Exists {
        body: Box<SelectStmt>,
        negated: bool,
    },
    InSubquery {
        expr: Box<Expr>,
        body: Box<SelectStmt>,
        negated: bool,
    },
    // some variants omitted
}

Scalar expression nodes the compiler handles.

Variants

Star

QualifiedStar(String)

Relation-qualified wildcard projection (table.* or alias.*).

Default

DEFAULT in an INSERT/UPDATE assignment. This is a mutation marker, not a scalar value, and must be resolved against the target column before expression evaluation.

Column(String)

Unqualified column reference (col).

QualifiedColumn

Qualified column reference (table.col or alias.col).

Fields

qualifier: String

column: String

Literal(Value)

Param(usize)

A positional bind parameter ($1, $2, …).

Func

text_match(...), knn_match(...), etc. - dispatched through the function registry.

Fields

name: String

binding: Option<FunctionBinding>

args: Vec<Expr>

distinct: bool

func(DISTINCT expr) - only meaningful for aggregate functions. Mirrors PostgreSQL’s agg_distinct.

order_by: Vec<OrderBy>

func(expr ORDER BY ...) - only meaningful for ordered aggregates (STRING_AGG, ARRAY_AGG, PERCENTILE_*).

filter: Option<Box<Expr>>

func(...) FILTER (WHERE expr) - aggregate-level row filter.

Array(Vec<Expr>)

ARRAY[1.0, 2.0, ...] literal - currently restricted to numeric elements (vectors).

Row(Vec<Expr>)

Anonymous SQL row constructor (ROW(...) or (a, b)).

Binary

lhs op rhs - comparison or arithmetic.

Fields

op: BinaryOp

lhs: Box<Expr>

rhs: Box<Expr>

UnaryMinus(Box<Expr>)

PostgreSQL prefix -, kept distinct from binary subtraction so the operand’s declared numeric width and overflow behavior survive lowering.

Not(Box<Expr>)

NOT expr.

And(Vec<Expr>)

cond_1 AND cond_2 AND ... (n-ary).

Or(Vec<Expr>)

cond_1 OR cond_2 OR ... (n-ary).

IsNull

expr IS NULL / expr IS NOT NULL.

Fields

expr: Box<Expr>

negated: bool

Between

expr BETWEEN low AND high.

Fields

expr: Box<Expr>

low: Box<Expr>

high: Box<Expr>

InList

expr IN (a, b, c) literal list.

Fields

expr: Box<Expr>

list: Vec<Expr>

negated: bool

WindowCall

func(args) OVER (PARTITION BY ... ORDER BY ...).

Fields

name: String

args: Vec<Expr>

spec: WindowSpec

Case

CASE [base] WHEN cond THEN result ... [ELSE default] END. base lifts simple-form CASE expr WHEN val THEN ... into an optional comparison anchor; searched-form CASE WHEN cond ... leaves it None.

Fields

base: Option<Box<Expr>>

when: Vec<(Expr, Expr)>

else_branch: Option<Box<Expr>>

Cast

CAST(expr AS type). The type name is preserved verbatim so the evaluator can apply the correct coercion.

Fields

expr: Box<Expr>

ty: String

ScalarSubquery(Box<SelectStmt>)

(SELECT ...) scalar subquery: yields a single row / single column value at evaluation time.

Exists

EXISTS (SELECT ...) – truthy when the body produces at least one row.

Fields

body: Box<SelectStmt>

negated: bool

InSubquery

expr [NOT] IN (SELECT ...) set membership against a subquery. Evaluator runs the body once per top-level expression and tests membership.

Fields

expr: Box<Expr>

body: Box<SelectStmt>

negated: bool

Implementations

impl Expr

pub fn qualified_column( qualifier: impl Into<String>, column: impl Into<String>, ) -> Self

pub fn contains_window(&self) -> bool

True when this expression tree contains a window function call.

pub fn contains_aggregate(&self) -> bool

True when this expression tree contains a built-in aggregate call.

pub fn contains_unqualified_column(&self) -> bool

True when this expression contains a column whose owning relation can only be determined after catalog schemas have been bound.

pub fn contains_function_with_unknown_strictness(&self) -> bool

True when this expression contains a function whose strictness cannot be decided without an engine catalog.

pub fn any_node(&self, hit: &dyn Fn(&Self) -> bool) -> bool

Whether hit matches this node or any scalar node below it. Subquery bodies are opaque because they own independent query trees.

Trait Implementations

impl Clone for Expr

fn clone(&self) -> Expr

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Expr

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for Expr

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for Expr

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

Equality operator ==.

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

Inequality operator !=.

impl Serialize for Expr

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

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for Expr