CREATE INDEX IF NOT EXISTS ix_qna_state_id_task_id ON qna_table (state_id, task_id);
CREATE INDEX IF NOT EXISTS ix_qna_task_id ON qna_table (task_id);

CREATE INDEX IF NOT EXISTS ix_qna_state_qna_id ON qna_state_change_table (qna_id);
CREATE INDEX IF NOT EXISTS ix_qna_state_change_user_ ON qna_state_change_table (user_);
CREATE INDEX IF NOT EXISTS ix_qna_state_change_task_id_user_ ON qna_state_change_table (task_id, user_);
