-- Migration: Add middle_name to users and split existing first_name values
ALTER TABLE users ADD COLUMN IF NOT EXISTS middle_name VARCHAR(100);

-- Split first_name into first_name + middle_name for users with multiple words
UPDATE users
SET
  middle_name = TRIM(SUBSTRING(first_name FROM POSITION(' ' IN first_name))),
  first_name = TRIM(SPLIT_PART(first_name, ' ', 1))
WHERE first_name LIKE '% %';