Struct UnnestOptions 

pub struct UnnestOptions {
    pub null_handling: NullHandling,
    pub recursions: Vec<RecursionUnnestOption>,
}

Options for unnesting a column that contains a list type, replicating values in the other, non nested rows.

Conceptually this operation is like joining each row with all the values in the list column.

The behavior with NULL and empty input lists is controlled by NullHandling. See its variants for full details.

Examples

Unnest(c1), null_handling: NullHandling::Drop

     ┌─────────┐ ┌─────┐                ┌─────────┐ ┌─────┐
     │ {1, 2}  │ │  A  │   Unnest       │    1    │ │  A  │
     ├─────────┤ ├─────┤                ├─────────┤ ├─────┤
     │  null   │ │  B  │                │    2    │ │  A  │
     ├─────────┤ ├─────┤ ────────────▶  ├─────────┤ ├─────┤
     │   {}    │ │  D  │                │    3    │ │  E  │
     ├─────────┤ ├─────┤                └─────────┘ └─────┘
     │   {3}   │ │  E  │                    c1        c2
     └─────────┘ └─────┘
       c1         c2

Unnest(c1), null_handling: NullHandling::Preserve

     ┌─────────┐ ┌─────┐                ┌─────────┐ ┌─────┐
     │ {1, 2}  │ │  A  │   Unnest       │    1    │ │  A  │
     ├─────────┤ ├─────┤                ├─────────┤ ├─────┤
     │  null   │ │  B  │                │    2    │ │  A  │
     ├─────────┤ ├─────┤ ────────────▶  ├─────────┤ ├─────┤
     │   {}    │ │  D  │                │  null   │ │  B  │
     ├─────────┤ ├─────┤                ├─────────┤ ├─────┤
     │   {3}   │ │  E  │                │    3    │ │  E  │
     └─────────┘ └─────┘                └─────────┘ └─────┘
       c1         c2                        c1        c2

Unnest(c1), null_handling: NullHandling::PreserveAndExpandEmpty

     ┌─────────┐ ┌─────┐                ┌─────────┐ ┌─────┐
     │ {1, 2}  │ │  A  │   Unnest       │    1    │ │  A  │
     ├─────────┤ ├─────┤                ├─────────┤ ├─────┤
     │  null   │ │  B  │                │    2    │ │  A  │
     ├─────────┤ ├─────┤ ────────────▶  ├─────────┤ ├─────┤
     │   {}    │ │  D  │                │  null   │ │  B  │
     ├─────────┤ ├─────┤                ├─────────┤ ├─────┤
     │   {3}   │ │  E  │                │  null   │ │  D  │
     └─────────┘ └─────┘                ├─────────┤ ├─────┤
       c1         c2                    │    3    │ │  E  │
                                        └─────────┘ └─────┘
                                            c1        c2

recursions instruct how a column should be unnested (e.g unnesting a column multiple time, with depth = 1 and depth = 2). Any unnested column not being mentioned inside this options is inferred to be unnested with depth = 1

Fields

null_handling: NullHandling

How to handle NULL and empty list values in the input column. Defaults to NullHandling::Preserve.

recursions: Vec<RecursionUnnestOption>

If specific columns need to be unnested multiple times (e.g at different depth), declare them here. Any unnested columns not being mentioned inside this option will be unnested with depth = 1

Implementations

impl UnnestOptions

pub fn new() -> Self

Create a new UnnestOptions with default values

pub fn with_null_handling(self, null_handling: NullHandling) -> Self

Set the NullHandling mode used when unnesting NULL or empty input lists.

pub fn with_preserve_nulls(self, preserve_nulls: bool) -> Self

Backward-compatible setter that maps the previous boolean preserve_nulls flag onto NullHandling.

true maps to NullHandling::Preserve; false maps to NullHandling::Drop. To opt into the new empty-list-preserving mode, call Self::with_null_handling directly with NullHandling::PreserveAndExpandEmpty.

pub fn preserve_nulls(&self) -> bool

Returns true if NULL input rows produce a single output row containing NULL.

pub fn expand_empty_as_null(&self) -> bool

Returns true if empty input lists should produce a single output row containing NULL.

pub fn with_recursions(self, recursion: RecursionUnnestOption) -> Self

Set the recursions for the unnest operation

Trait Implementations

impl Clone for UnnestOptions

fn clone(&self) -> UnnestOptions

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for UnnestOptions

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

Formats the value using the given formatter.

impl Default for UnnestOptions

fn default() -> Self

Returns the “default value” for a type.

impl Eq for UnnestOptions

impl Hash for UnnestOptions

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 PartialEq for UnnestOptions

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

Equality operator ==.

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

Inequality operator !=.

impl PartialOrd for UnnestOptions

fn partial_cmp(&self, other: &UnnestOptions) -> 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 StructuralPartialEq for UnnestOptions