Enum Expr

datafusion/expr/src/expr.rs:326–434

/// ```
#[derive(Clone, PartialEq, PartialOrd, Eq, Debug, Hash)]
pub enum Expr {
    /// An expression with a specific name.
    Alias(Alias),
    /// A named reference to a qualified field in a schema.
    Column(Column),
    /// A named reference to a variable in a registry.
    ScalarVariable(FieldRef, Vec<String>),
    /// A constant value along with associated [`FieldMetadata`].
    Literal(ScalarValue, Option<FieldMetadata>),
    /// A binary expression such as "age > 21"
    BinaryExpr(BinaryExpr),
    /// LIKE expression
    Like(Like),
    /// LIKE expression that uses regular expressions
    SimilarTo(Like),
    /// Negation of an expression. The expression's type must be a boolean to make sense.
    Not(Box<Expr>),
    /// True if argument is not NULL, false otherwise. This expression itself is never NULL.
    IsNotNull(Box<Expr>),
    /// True if argument is NULL, false otherwise. This expression itself is never NULL.
    IsNull(Box<Expr>),
    /// True if argument is true, false otherwise. This expression itself is never NULL.
    IsTrue(Box<Expr>),
    /// True if argument is  false, false otherwise. This expression itself is never NULL.
    IsFalse(Box<Expr>),
    /// True if argument is NULL, false otherwise. This expression itself is never NULL.
    IsUnknown(Box<Expr>),
    /// True if argument is FALSE or NULL, false otherwise. This expression itself is never NULL.
    IsNotTrue(Box<Expr>),
    /// True if argument is TRUE OR NULL, false otherwise. This expression itself is never NULL.
    IsNotFalse(Box<Expr>),
    /// True if argument is TRUE or FALSE, false otherwise. This expression itself is never NULL.
    IsNotUnknown(Box<Expr>),
    /// arithmetic negation of an expression, the operand must be of a signed numeric data type
    Negative(Box<Expr>),
    /// Whether an expression is between a given range.
    Between(Between),
    /// A CASE expression (see docs on [`Case`])
    Case(Case),
    /// Casts the expression to a given type and will return a runtime error if the expression cannot be cast.
    /// This expression is guaranteed to have a fixed type.
    Cast(Cast),
    /// Casts the expression to a given type and will return a null value if the expression cannot be cast.
    /// This expression is guaranteed to have a fixed type.
    TryCast(TryCast),
    /// Call a scalar function with a set of arguments.
    ScalarFunction(ScalarFunction),
    /// Calls an aggregate function with arguments, and optional
    /// `ORDER BY`, `FILTER`, `DISTINCT` and `NULL TREATMENT`.
    ///
    /// See also [`ExprFunctionExt`] to set these fields.
    ///
    /// [`ExprFunctionExt`]: crate::expr_fn::ExprFunctionExt
    AggregateFunction(AggregateFunction),
    /// Call a window function with a set of arguments.
    WindowFunction(Box<WindowFunction>),
    /// Returns whether the list contains the expr value.
    InList(InList),