代码中的一个问题是子查询与外部查询不相关（通常，应该有一个供应商编号过滤器）。此外，在其中一个WHERE子句中混合了AND和OR，这可能并不符合您的要求。
根据你的问题陈述，我认为你不需要子查询，而是需要条件聚合。类似于：

SELECT SUPPLIER_NO, SUPPLIER,
    SUM(
        CASE
            WHEN DELIVERY_DATE BETWEEN TRUNC(SYSDATE, 'YEAR') AND TRUNC(SYSDATE) 
            THEN ORDER_QTY 
            ELSE 0 
        END
    ) as YTD,
    SUM(
        CASE 
            WHEN STATE IN ('CONFIRMED', 'RELEASED') AND DELIVERY_DATE >= SYSDATE 
            THEN ORDER_QTY 
            ELSE 0 
        END
    ) as OVERDUE
FROM MY_TABLE
GROUP BY SUPPLIER_NO, SUPPLIER

我也更喜欢条件聚合方法更好（见GMB的回答），但这里有一个相关的查询方法：

SELECT 
    T1.SUPPLIER_NO,
    T1.SUPPLIER,
(SELECT 
    SUM(ORDER_QTY)
    FROM  MY_TABLE T2 
    WHERE  
        T2.SUPPLIER_NO = T1.SUPPLIER_NO
        AND DELIVERY_DATE BETWEEN TRUNC(SYSDATE, 'YEAR') AND TRUNC(SYSDATE)) AS YTD,
(SELECT 
    SUM(ORDERQTY)
    FROM MY_TABLE T3
    WHERE  
        T3.SUPPLIER_NO = T1.SUPPLIER_NO
        AND (STATE = 'CONFIRMED' OR STATE = 'RELEASED')
        AND    DELIVERY_DATE >= SYSDATE) AS OVERDUE,
FROM 
    MY_TABLE T1