Enum SqlExpr 

pub enum SqlExpr {
    Column(String),
    Literal(Value),
    BinaryOp {
        left: Box<SqlExpr>,
        op: BinaryOp,
        right: Box<SqlExpr>,
    },
    Negate(Box<SqlExpr>),
    Function {
        name: String,
        args: Vec<SqlExpr>,
    },
    Cast {
        expr: Box<SqlExpr>,
        to_type: CastType,
    },
    Case {
        operand: Option<Box<SqlExpr>>,
        when_thens: Vec<(SqlExpr, SqlExpr)>,
        else_expr: Option<Box<SqlExpr>>,
    },
    Coalesce(Vec<SqlExpr>),
    NullIf(Box<SqlExpr>, Box<SqlExpr>),
    IsNull {
        expr: Box<SqlExpr>,
        negated: bool,
    },
}

A serializable SQL expression that can be evaluated against a JSON document.

Variants

Column(String)

Column reference: extract field value from the document.

Literal(Value)

Literal value.

BinaryOp

Binary operation: left op right.

Fields

left: Box<SqlExpr>

op: BinaryOp

right: Box<SqlExpr>

Negate(Box<SqlExpr>)

Unary negation: -expr or NOT expr.

Function

Scalar function call.

Fields

name: String

args: Vec<SqlExpr>

Cast

CAST(expr AS type).

Fields

expr: Box<SqlExpr>

to_type: CastType

Case

CASE WHEN cond1 THEN val1 … ELSE default END.

Fields

operand: Option<Box<SqlExpr>>

when_thens: Vec<(SqlExpr, SqlExpr)>

else_expr: Option<Box<SqlExpr>>

Coalesce(Vec<SqlExpr>)

COALESCE(expr1, expr2, …): first non-null value.

NullIf(Box<SqlExpr>, Box<SqlExpr>)

NULLIF(expr1, expr2): returns NULL if expr1 = expr2, else expr1.

IsNull

IS NULL / IS NOT NULL.

Fields

expr: Box<SqlExpr>

negated: bool

Implementations

impl SqlExpr

pub fn eval(&self, doc: &Value) -> Value

Evaluate this expression against a JSON document.

Returns a JSON value. Column references look up fields in the document. Missing fields return null. Arithmetic on non-numeric values returns null.

Trait Implementations

impl Clone for SqlExpr

fn clone(&self) -> SqlExpr

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for SqlExpr

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for SqlExpr

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for SqlExpr

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

where __S: Serializer,

Serialize this value into the given Serde serializer.