无法合并DB2

如果DB2查询中没有结果，我将尝试显示“0”。联合不适合我。这是DB2LUBV8.2。我该怎么做

SELECT 'Stuff',
COALESCE((SUM(OI.QUANTITY)),0)
FROM DB2ADMIN.ORDERS O INNER JOIN DB2ADMIN.ORDERITEMS OI ON O.ORDERS_ID = OI.ORDERS_ID
WHERE DATE(O.TIMEPLACED) = (DATE(CURRENT DATE) - 1 DAYS)
AND OI.CATENTRY_ID = 000001    
GROUP BY DATE(O.TIMEPLACED)

您可以使用a来执行此操作

WITH MYCTE (MYSTUFF, MYSUM) AS (
SELECT 'Stuff',0
FROM SYSIBM.SYSDUMMY1
UNION ALL
SELECT 'Stuff', SUM(OI.QUANTITY)
FROM DB2ADMIN.ORDERS O INNER JOIN DB2ADMIN.ORDERITEMS OI ON O.ORDERS_ID = OI.ORDERS_ID
WHERE DATE(O.TIMEPLACED) = (DATE(CURRENT DATE) - 1 DAYS)
AND OI.CATENTRY_ID = 000001    
GROUP BY DATE(O.TIMEPLACED))
SELECT MYSTUFF, SUM(MYSUM)          
FROM MYCTE
GROUP BY MYSTUFF;

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可能合并正在工作，但由于null，总和失败，您是否尝试在总和中使用合并或NVL？i、 e

SELECT 'Stuff',
(SUM(COALESCE(OI.QUANTITY,0)))
FROM DB2ADMIN.ORDERS O INNER JOIN DB2ADMIN.ORDERITEMS OI ON O.ORDERS_ID = OI.ORDERS_ID
WHERE DATE(O.TIMEPLACED) = (DATE(CURRENT DATE) - 1 DAYS)
AND OI.CATENTRY_ID = 000001    
GROUP BY DATE(O.TIMEPLACED)

---

如果您解释

COALESCE

“不起作用”的原因，可能会有所帮助。你得到了什么结果？你期待什么？