How to fix Cannot insert multiple commands into prepared statement in PostgreSQL

-- Problematic query (multiple commands in one prepared statement)
ALTER TABLE users ADD COLUMN old_id INTEGER;
UPDATE users SET old_id = id;
DELETE FROM users WHERE old_id IS NULL;

// Node.js with node-postgres (pg) library
const client = new Client();
await client.connect();

try {
  // Execute each statement separately
  await client.query('ALTER TABLE users ADD COLUMN old_id INTEGER');
  await client.query('UPDATE users SET old_id = $1 WHERE id = $2', [value, id]);
  await client.query('DELETE FROM users WHERE old_id IS NULL');
} finally {
  await client.end();
}

// Execute with transaction
const client = new Client();
await client.connect();

try {
  await client.query('BEGIN');
  await client.query('ALTER TABLE users ADD COLUMN old_id INTEGER');
  await client.query('UPDATE users SET old_id = $1 WHERE id = $2', [value, id]);
  await client.query('DELETE FROM users WHERE old_id IS NULL');
  await client.query('COMMIT');
} catch (error) {
  await client.query('ROLLBACK');
  throw error;
} finally {
  await client.end();
}

CREATE FUNCTION migrate_user_ids() RETURNS void AS $$
BEGIN
  ALTER TABLE users ADD COLUMN IF NOT EXISTS old_id INTEGER;
  UPDATE users SET old_id = id;
  DELETE FROM users WHERE old_id IS NULL;
END;
$$ LANGUAGE plpgsql;

// Much simpler - just one statement
await client.query('SELECT migrate_user_ids()');

# Using Flyway
flyway migrate

# Using node-migrate
npm run migrate

// PostgreSQL JDBC Driver (Java)
// Disable prepared statement mode for multi-statement execution
Properties props = new Properties();
props.setProperty("statement_timeout", "30000");
// Some drivers allow disabling prepared statements

// node-postgres (JS)
// Always uses prepared statements for parameterized queries
// Must split statements or use unprepared queries carefully