Scalar Functions Reference¶

Complete reference for YAML scalar functions.

Extraction Functions¶

yaml_extract¶

yaml_extract(yaml YAML, path VARCHAR) → YAML

Extracts a value at the specified path.

Parameter	Type	Description
`yaml`	YAML	Source YAML value
`path`	VARCHAR	JSONPath-like expression

Returns: YAML value at path, or NULL if not found.

SELECT yaml_extract('{user: {name: John}}'::YAML, '$.user.name');
-- Returns: John

yaml_extract_string¶

yaml_extract_string(yaml YAML, path VARCHAR) → VARCHAR

Extracts a value as a string.

Parameter	Type	Description
`yaml`	YAML	Source YAML value
`path`	VARCHAR	JSONPath-like expression

Returns: VARCHAR representation of value, or NULL.

SELECT yaml_extract_string('{count: 42}'::YAML, '$.count');
-- Returns: '42'

yaml_exists¶

yaml_exists(yaml YAML, path VARCHAR) → BOOLEAN

Checks if a path exists.

Parameter	Type	Description
`yaml`	YAML	Source YAML value
`path`	VARCHAR	JSONPath-like expression

Returns: TRUE if path exists, FALSE otherwise.

SELECT yaml_exists('{name: John}'::YAML, '$.age');
-- Returns: false

yaml_type¶

yaml_type(yaml YAML) → VARCHAR
yaml_type(yaml YAML, path VARCHAR) → VARCHAR

Returns the type of a YAML value.

Parameter	Type	Description
`yaml`	YAML	Source YAML value
`path`	VARCHAR	Optional path expression

Returns: One of: 'object', 'array', 'scalar', 'null'

SELECT yaml_type('[1, 2, 3]'::YAML);
-- Returns: 'array'

yaml_keys¶

yaml_keys(yaml YAML) → VARCHAR[]
yaml_keys(yaml YAML, path VARCHAR) → VARCHAR[]

Returns keys of a YAML object.

Parameter	Type	Description
`yaml`	YAML	Source YAML value
`path`	VARCHAR	Optional path to object

Returns: Array of key names, or NULL if not an object.

SELECT yaml_keys('{a: 1, b: 2, c: 3}'::YAML);
-- Returns: [a, b, c]

yaml_array_length¶

yaml_array_length(yaml YAML) → BIGINT
yaml_array_length(yaml YAML, path VARCHAR) → BIGINT

Returns the length of a YAML array.

Parameter	Type	Description
`yaml`	YAML	Source YAML value
`path`	VARCHAR	Optional path to array

Returns: Number of elements, or NULL if not an array.

SELECT yaml_array_length('[1, 2, 3, 4, 5]'::YAML);
-- Returns: 5

Conversion Functions¶

yaml_to_json¶

yaml_to_json(yaml YAML) → JSON

Converts YAML to JSON.

Parameter	Type	Description
`yaml`	YAML	YAML value to convert

Returns: JSON equivalent.

SELECT yaml_to_json('name: John\nage: 30'::YAML);
-- Returns: {"name":"John","age":30}

value_to_yaml¶

value_to_yaml(value ANY) → YAML

Converts any DuckDB value to YAML.

Parameter	Type	Description
`value`	ANY	Value to convert

Returns: YAML representation.

SELECT value_to_yaml({'name': 'John', 'scores': [1, 2, 3]});
-- Returns: name: John\nscores:\n  - 1\n  - 2\n  - 3

format_yaml¶

format_yaml(value ANY, style := 'flow', multiline := 'auto', indent := 2) → VARCHAR

Formats a value as YAML with configurable style.

Parameter	Type	Description
`value`	ANY	Value to format as YAML
`style`	VARCHAR	`'flow'` or `'block'` (named parameter)
`multiline`	VARCHAR	`'auto'`, `'literal'`, or `'quoted'` (named parameter)
`indent`	INTEGER	`1`-`10`, indentation width (named parameter)

Returns: Formatted YAML string.

SELECT format_yaml({'a': 1, 'b': 2}, style := 'block');
-- Returns:
-- a: 1
-- b: 2

-- Multiline strings with literal block scalars
SELECT format_yaml({'msg': E'hello\nworld'}, style := 'block', multiline := 'literal');
-- Returns:
-- msg: |
--   hello
--   world

-- Custom indentation
SELECT format_yaml({'a': {'b': 1}}, style := 'block', indent := 4);
-- Returns:
-- a:
--     b: 1

from_yaml¶

from_yaml(yaml_string VARCHAR, structure STRUCT) → STRUCT

Parses YAML into a structured type.

Parameter	Type	Description
`yaml_string`	VARCHAR	YAML string to parse
`structure`	STRUCT	Template defining output structure

Returns: Struct matching the template.

SELECT from_yaml('name: John\nage: 30', {'name': '', 'age': 0});
-- Returns: {'name': John, 'age': 30}

Construction Functions¶

yaml_build_object¶

yaml_build_object(key1, value1, key2, value2, ...) → YAML

Builds a YAML object from key-value pairs.

Parameter	Type	Description
`key`	VARCHAR	Object key
`value`	ANY	Value for key

Returns: YAML object.

SELECT yaml_build_object('name', 'John', 'age', 30);
-- Returns: {name: John, age: 30}

Utility Functions¶

yaml_valid¶

yaml_valid(yaml_string VARCHAR) → BOOLEAN

Checks if a string is valid YAML.

Parameter	Type	Description
`yaml_string`	VARCHAR	String to validate

Returns: TRUE if valid, FALSE otherwise.

SELECT yaml_valid('name: : invalid');
-- Returns: false

yaml_set_default_style¶

yaml_set_default_style(style VARCHAR) → VARCHAR

Sets the default output style.

Parameter	Type	Description
`style`	VARCHAR	`'flow'` or `'block'`

Returns: Confirmation message.

SELECT yaml_set_default_style('block');

yaml_get_default_style¶

yaml_get_default_style() → VARCHAR

Returns the current default style.

Returns: 'flow' or 'block'.

SELECT yaml_get_default_style();
-- Returns: flow

Type Casts¶

YAML to JSON¶

yaml_value::JSON
CAST(yaml_value AS JSON)

JSON to YAML¶

json_value::YAML
CAST(json_value AS YAML)

VARCHAR to YAML¶

string_value::YAML
CAST(string_value AS YAML)

YAML to VARCHAR¶

yaml_value::VARCHAR
CAST(yaml_value AS VARCHAR)