ALTER TABLE tracks ADD COLUMN IF NOT EXISTS share_count BIGINT UNSIGNED NOT NULL DEFAULT 0 AFTER dislike_count;
ALTER TABLE tracks ADD COLUMN IF NOT EXISTS rank_score DECIMAL(18,2) NOT NULL DEFAULT 0.00 AFTER share_count;
ALTER TABLE tracks ADD COLUMN IF NOT EXISTS rank_updated_at DATETIME NULL AFTER rank_score;
CREATE INDEX IF NOT EXISTS idx_tracks_rank_score ON tracks(rank_score);