VECTOR

Syntax

vector(scalar_type, dimension)
vector(dimension)

• scalar type is the element type in the vector, optional, the default value is float type. Supports tinyint/int/float
• dimension: only specifies the dimension

Example:

CREATE TABLE test_vector (
    vec1 vector(float, 512),  -- Specify element type as float, dimension as 512
    vec2 vector(512),         -- Default element type is float, dimension is 512
    vec3 vector(tinyint, 128) -- Specify element type as tinyint, dimension as 128
);

Create Vector:

SELECT vector(1, 2, 3); -- Automatically infer the element type based on the provided values and create a vector

Usage Restrictions

• The current version of the vector type does not support comparison operations, so it cannot be used in ORDER BY or GROUP BY clauses.
• The current client does not implement the vector type, but it is supported in the SQL engine. Therefore, when you execute a select statement with a vector type in the result, an error will occur: Unsupported data type: VECTOR_TYPE

Vector Type Conversion

Vector types support conversion to and from array types, as well as conversion from string types to vector types:

1. Implicit Conversion: In most cases, vector types can be directly converted to array types, trying to keep the element types unchanged.
2. Array to Vector: Array types can also be converted to vector types, but the array length must match the vector dimension. If they do not match, the conversion result will be NULL.
3. String to Vector: Strings in the format '[1, 2, 3]' can be converted to vector types (extra spaces will be ignored).

Performance Tip: For medium to high dimensions (dimension >= 128) vectors, using cast('[1,2,3,4]' as vector(4)) is slightly more efficient than vector(1,2,3,4).

Example:

-- Implicitly convert vector to array
SELECT array_append(vector(1,2,3), 4);

-- Calculate the L2 distance between two vectors
SELECT l2_distance(array(1,2,3), vector(3,2,1));

-- Explicitly convert string to vector
SELECT cast('[1,2,3,4]' as vector(4));