Resolved: Get an error when using DISTINCT in SELECT Statement

SELECT
CASE 
    WHEN SUBSTR(fact.delivery_time,1,10) = from_timestamp(now(), 'yyyy-MM-dd') THEN from_timestamp(to_timestamp(SUBSTR(fact.delivery_time,1,10), 'yyyy-MM-dd'),'dd.MM.yyyy')
    WHEN SUBSTR(fact.delivery_time,1,10) = from_timestamp(DAYS_ADD(now(),-1), 'yyyy-MM-dd') THEN from_timestamp(DAYS_ADD(now(),-1),'dd.MM.yyyy')
    WHEN SUBSTR(fact.delivery_time,1,10) <= from_timestamp(DAYS_ADD(now(),-2), 'yyyy-MM-dd') THEN 'Older'
END AS delivery_day,
DISTINCT fact.order_id AS ORDER_ID
FROM fact
JOIN article art ON art.article_id = fact.article_id
WHERE fact.status IN ('OPEN', 'RECEIVING', 'REGISTERED')
AND fact.type !='RETURN'
AND art.classification_name LIKE '15deg%'
GROUP BY
    fact.delivery_time;

SELECT
CASE 
    WHEN SUBSTR(fact.delivery_time,1,10) = from_timestamp(now(), 'yyyy-MM-dd') THEN from_timestamp(to_timestamp(SUBSTR(fact.delivery_time,1,10), 'yyyy-MM-dd'),'dd.MM.yyyy')
    WHEN SUBSTR(fact.delivery_time,1,10) = from_timestamp(DAYS_ADD(now(),-1), 'yyyy-MM-dd') THEN from_timestamp(DAYS_ADD(now(),-1),'dd.MM.yyyy')
    WHEN SUBSTR(fact.delivery_time,1,10) <= from_timestamp(DAYS_ADD(now(),-2), 'yyyy-MM-dd') THEN 'Older'
END AS delivery_day,
fact.order_id AS ORDER_ID
FROM fact
JOIN article art ON art.article_id = fact.article_id
WHERE fact.status IN ('OPEN', 'RECEIVING', 'REGISTERED')
AND fact.type !='RETURN'
AND art.classification_name LIKE '15deg%'
GROUP BY
    delivery_day,
    ORDER_ID;