In Postgres, perform a partial match on an encrypted column value

In PostgreSQL, executing a partial match on an encrypted column value is complex due to the nature of encrypted data. The standard encryption methods alter the data in a way that makes partial text search impractical. However, you can use the pgcrypto extension for encryption and the pg_trgm extension for text search on non-encrypted or deterministically encrypted data. Here's an illustration:

-- Enable necessary extensions
CREATE EXTENSION IF NOT EXISTS pgcrypto;
CREATE EXTENSION IF NOT EXISTS pg_trgm;

-- Create a table to store encrypted data
CREATE TABLE encrypted_data (
    id SERIAL PRIMARY KEY,
    encrypted_column BYTEA -- Encrypted data is stored in binary format
);

-- Insert encrypted data using pgcrypto's pgp_sym_encrypt function
INSERT INTO encrypted_data (encrypted_column)
VALUES 
    (pgp_sym_encrypt('value 1', 'encryption_key')),
    (pgp_sym_encrypt('value 2', 'encryption_key'));

-- For a partial match, you would first need to decrypt the data, 
-- which requires a full table scan and then apply the pg_trgm search:
SELECT id, pgp_sym_decrypt(encrypted_column, 'encryption_key') AS decrypted
FROM encrypted_data
WHERE pgp_sym_decrypt(encrypted_column, 'encryption_key') LIKE '%value%';

This approach decrypts the data and then performs a partial match on the decrypted result. Note that this method is not efficient for large datasets due to the full table scan and decryption process required for each query. It's also important to understand that performing such operations can expose sensitive data to risks if not handled securely. Always consider the security implications of decrypting data in this manner and ensure that appropriate permissions and security measures are in place.