-- Migration 004: Exam question quality gate counters
-- Adds counters to exam_sets so the UI can report how many questions
-- were skipped as duplicates and how many were rejected as invalid.
--
-- Idempotent — safe to run multiple times.

ALTER TABLE exam_sets
    ADD COLUMN IF NOT EXISTS skipped_duplicate_count INT UNSIGNED NOT NULL DEFAULT 0,
    ADD COLUMN IF NOT EXISTS rejected_invalid_count  INT UNSIGNED NOT NULL DEFAULT 0;