COSINE_DISTANCE

Measuring similarity using the cosine_distance function in PlaidCloud Lakehouse

This document provides an overview of the cosine_distance function in PlaidCloud Lakehouse and demonstrates how to measure document similarity using this function.

The cosine_distance function in PlaidCloud Lakehouse is a built-in function that calculates the cosine distance between two vectors. It is commonly used in natural language processing tasks, such as document similarity and recommendation systems.

Cosine distance is a measure of similarity between two vectors, based on the cosine of the angle between them. The function takes two input vectors and returns a value between 0 and 1, with 0 indicating identical vectors and 1 indicating orthogonal (completely dissimilar) vectors.

Analyze Syntax

func.cosine_distance(<vector1>, <vector2>)

SQL Examples

Creating a Table and Inserting Sample Data

Let's create a table to store some sample text documents and their corresponding embeddings:

CREATE TABLE articles (
    id INT,
    title VARCHAR,
    content VARCHAR,
    embedding ARRAY(FLOAT32)
);

Now, let's insert some sample documents into the table:

INSERT INTO articles (id, title, content, embedding)
VALUES
    (1, 'Python for Data Science', 'Python is a versatile programming language widely used in data science...', ai_embedding_vector('Python is a versatile programming language widely used in data science...')),
    (2, 'Introduction to R', 'R is a popular programming language for statistical computing and graphics...', ai_embedding_vector('R is a popular programming language for statistical computing and graphics...')),
    (3, 'Getting Started with SQL', 'Structured Query Language (SQL) is a domain-specific language used for managing relational databases...', ai_embedding_vector('Structured Query Language (SQL) is a domain-specific language used for managing relational databases...'));

Querying for Similar Documents

Now, let's find the documents that are most similar to a given query using the cosine_distance function:

SELECT
    id,
    title,
    content,
    cosine_distance(embedding, ai_embedding_vector('How to use Python in data analysis?')) AS similarity
FROM
    articles
ORDER BY
    similarity ASC
    LIMIT 3;

Result:

┌──────┬──────────────────────────┬─────────────────────────────────────────────────────────────────────────────────────────────────────────┬────────────┐
│ id   │ title                    │ content                                                                                                 │ similarity │
├──────┼──────────────────────────┼─────────────────────────────────────────────────────────────────────────────────────────────────────────┼────────────┤
│    1 │ Python for Data Science  │ Python is a versatile programming language widely used in data science...                               │  0.1142081 │
│    2 │ Introduction to R        │ R is a popular programming language for statistical computing and graphics...                           │ 0.18741018 │
│    3 │ Getting Started with SQL │ Structured Query Language (SQL) is a domain-specific language used for managing relational databases... │ 0.25137568 │
└──────┴──────────────────────────┴─────────────────────────────────────────────────────────────────────────────────────────────────────────┴────────────┘