Struct CaseLiteral 

pub struct CaseLiteral {
    pub lookup: BTreeMap<Row, usize>,
    pub return_type: SqlColumnType,
}

Evaluates a CASE expression by looking up the input datum in a BTreeMap.

The input expression (exprs[0]) is evaluated once, packed into a temporary Row, and looked up in lookup. If found, the corresponding result expression (exprs[idx]) is evaluated; otherwise the fallback (exprs.last()) is evaluated. NULL inputs go straight to the fallback (since SQL NULL = x is always NULL/falsy).

Fields

lookup: BTreeMap<Row, usize>

Map from literal values (as single-datum Rows) to indices in the exprs vector.

return_type: SqlColumnType

The output type of this CASE expression.

Trait Implementations

impl Clone for CaseLiteral

fn clone(&self) -> CaseLiteral

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for CaseLiteral

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for CaseLiteral

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Display for CaseLiteral

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

Formats the value using the given formatter.

impl From<CaseLiteral> for VariadicFunc

fn from(variant: CaseLiteral) -> Self

Converts to this type from the input type.

impl Hash for CaseLiteral

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 LazyVariadicFunc for CaseLiteral

fn eval<'a>( &'a self, datums: &[Datum<'a>], temp_storage: &'a RowArena, exprs: &'a [MirScalarExpr], ) -> Result<Datum<'a>, EvalError>

fn output_type(&self, _input_types: &[SqlColumnType]) -> SqlColumnType

The output SqlColumnType of this function.

fn propagates_nulls(&self) -> bool

Whether this function will produce NULL on NULL input.

fn introduces_nulls(&self) -> bool

Whether this function will produce NULL on non-NULL input.

fn could_error(&self) -> bool

Whether this function might error on non-error input.

fn is_monotone(&self) -> bool

Returns true if the function is monotone.

fn is_associative(&self) -> bool

Returns true if the function is associative.

fn is_infix_op(&self) -> bool

Returns true if the function is an infix operator.

impl MzReflect for CaseLiteral

fn add_to_reflected_type_info(rti: &mut ReflectedTypeInfo)

Adds names and types of the fields of the struct or enum to rti.

impl Ord for CaseLiteral

fn cmp(&self, other: &CaseLiteral) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for CaseLiteral

fn eq(&self, other: &CaseLiteral) -> 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 PartialOrd for CaseLiteral

fn partial_cmp(&self, other: &CaseLiteral) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Serialize for CaseLiteral

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

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Eq for CaseLiteral

impl StructuralPartialEq for CaseLiteral