-- 304_eid_study_weakness_idx.sql — 301_eid_study_weakness.sql 분리본 (single-statement). asyncpg 러너가 prepared statement 로 처리해 multi-statement 거부 → 1 stmt/파일. 내용 불변.

CREATE INDEX IF NOT EXISTS idx_eid_weakness_user_current
    ON eid_study_weakness (user_id, created_at DESC) WHERE status = 'active';