Enum Expr 

pub enum Expr {
    Column {
        table: Option<String>,
        name: String,
        index: Option<usize>,
    },
    Literal(Value),
    Parameter {
        index: usize,
    },
    BinaryOp {
        left: Box<Expr>,
        op: BinaryOp,
        right: Box<Expr>,
    },
    UnaryOp {
        op: UnaryOp,
        expr: Box<Expr>,
    },
    Function {
        name: String,
        args: Vec<Expr>,
    },
    Aggregate {
        func: AggregateFunction,
        arg: Option<Box<Expr>>,
        distinct: bool,
    },
    Case {
        operand: Option<Box<Expr>>,
        when_clauses: Vec<(Expr, Expr)>,
        else_result: Option<Box<Expr>>,
    },
    Between {
        expr: Box<Expr>,
        low: Box<Expr>,
        high: Box<Expr>,
        negated: bool,
    },
    InList {
        expr: Box<Expr>,
        list: Vec<Expr>,
        negated: bool,
    },
    Like {
        expr: Box<Expr>,
        pattern: String,
        negated: bool,
    },
    Wildcard,
    QualifiedWildcard(String),
    Window(WindowFunction),
    ScalarSubquery {
        subquery_id: usize,
        correlated: bool,
    },
    Exists {
        subquery_id: usize,
        negated: bool,
    },
    InSubquery {
        expr: Box<Expr>,
        subquery_id: usize,
        negated: bool,
    },
    AnySubquery {
        expr: Box<Expr>,
        op: SubqueryCompareOp,
        subquery_id: usize,
    },
    AllSubquery {
        expr: Box<Expr>,
        op: SubqueryCompareOp,
        subquery_id: usize,
    },
}

Expression tree

Variants

Column

Column reference

Fields

table: Option<String>

name: String

index: Option<usize>

Literal(Value)

Literal value

Parameter

Parameter placeholder for prepared statements Index is 0-based (? is index 0, $1 maps to index 0, $2 to index 1, etc.)

Fields

index: usize

BinaryOp

Binary operation

Fields

left: Box<Expr>

op: BinaryOp

right: Box<Expr>

UnaryOp

Unary operation

Fields

op: UnaryOp

expr: Box<Expr>

Function

Function call

Fields

name: String

args: Vec<Expr>

Aggregate

Aggregate function

Fields

func: AggregateFunction

arg: Option<Box<Expr>>

distinct: bool

Case

CASE WHEN … THEN … ELSE … END

Fields

operand: Option<Box<Expr>>

when_clauses: Vec<(Expr, Expr)>

else_result: Option<Box<Expr>>

Between

BETWEEN

Fields

expr: Box<Expr>

low: Box<Expr>

high: Box<Expr>

negated: bool

InList

IN (list)

Fields

expr: Box<Expr>

list: Vec<Expr>

negated: bool

Like

LIKE pattern

Fields

expr: Box<Expr>

pattern: String

negated: bool

Wildcard

Wildcard (*) for SELECT *

QualifiedWildcard(String)

Qualified wildcard (table.) for SELECT table.

Window(WindowFunction)

Window function expression

ScalarSubquery

Scalar subquery - returns a single value e.g., SELECT name, (SELECT COUNT(*) FROM orders WHERE user_id = users.id)

Fields

subquery_id: usize

Unique identifier for the subquery (for correlation tracking)

correlated: bool

Whether this subquery is correlated (references outer query)

Exists

EXISTS subquery e.g., WHERE EXISTS (SELECT 1 FROM orders WHERE user_id = users.id)

Fields

subquery_id: usize

negated: bool

InSubquery

IN subquery e.g., WHERE id IN (SELECT user_id FROM orders)

Fields

expr: Box<Expr>

subquery_id: usize

negated: bool

AnySubquery

ANY/SOME subquery comparison e.g., WHERE x > ANY (SELECT value FROM t)

Fields

expr: Box<Expr>

op: SubqueryCompareOp

subquery_id: usize

AllSubquery

ALL subquery comparison e.g., WHERE x > ALL (SELECT value FROM t)

Fields

expr: Box<Expr>

op: SubqueryCompareOp

subquery_id: usize

Implementations

impl Expr

pub fn column(name: impl Into<String>) -> Self

Create a column reference

pub fn qualified_column( table: impl Into<String>, name: impl Into<String>, ) -> Self

Create a qualified column reference

pub fn literal(value: impl Into<Value>) -> Self

Create a literal

pub fn binary(left: Expr, op: BinaryOp, right: Expr) -> Self

Create a binary operation

pub fn and(left: Expr, right: Expr) -> Self

Create an AND expression

pub fn or(left: Expr, right: Expr) -> Self

Create an OR expression

pub fn parameter(index: usize) -> Self

Create a parameter placeholder

pub fn resolve_indices(&mut self, column_map: &HashMap<String, usize>)

Pre-resolve column indices from a column map so that eval() can use direct index access (O(1)) instead of HashMap lookups per row. Call once before a row loop, then use the resolved expression for all rows.

pub fn referenced_columns(&self, out: &mut Vec<usize>)

Collect all resolved column indices referenced by this expression.

pub fn eval( &self, row: &[Value], column_map: &HashMap<String, usize>, ) -> Result<Value>

Evaluate expression against a row

pub fn contains_aggregate(&self) -> bool

Check if expression contains aggregates

pub fn collect_column_references(&self) -> Vec<(Option<String>, String)>

Collect all column references in this expression Returns tuples of (table, column_name)

pub fn contains_window_function(&self) -> bool

Check if expression contains window functions

pub fn contains_subquery(&self) -> bool

Check if expression contains subqueries

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 PartialEq for Expr

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for Expr