SQL 到 return 连接中的单行

Question

有人知道如何在下面的示例中将结果限制为一行吗？我得到两行，因为 STOCK 值有两个不同的结果。不确定如何添加 MAX 或类似的东西，所以连接的结果只会给我一行...

SELECT * FROM abtItemTbl abt
LEFT JOIN BT_PUBLISHED_WCID_LEVEL bt 
    ON abt.UDA_WCID = bt.PRODUCT_ID
    AND bt.DISPLAY_NAME IS NOT NULL
    AND bt.COUNT_OF_WCID_IMAGES IS NOT NULL
WHERE abt.ITEM_PARENT IS NULL
AND abt.UDA_WCID = '49x1794x116430'

Answer 1

您可能希望在加入之前进行汇总：

LEFT JOIN
(SELECT bt.PRODUCT_ID, SUM(STOCK) as STOCK
 FROM BT_PUBLISHED_WCID_LEVEL bt 
 WHERE bt.DISPLAY_NAME IS NOT NULL AND
       bt.COUNT_OF_WCID_IMAGES IS NOT NULL
 GROUP BY bt.PRODUCT_ID
) bt
ON abt.UDA_WCID = bt.PRODUCT_ID

SQL 到 return 连接中的单行

SQL to return a single line in the join

sql

sql-server-2014