Question

SELECT 
t1.aID, t1.firstname, t1.lastname,
SUM(t2.price) AS sumsales
FROM t3
  INNER JOIN t1
    ON t3.aID = t1.aID
  INNER JOIN t2
    ON t3.wID = t2.wID
GROUP BY (t1.aID, t1.firstname, t1.lastname)
ORDER BY sumsales DESC

如何从此oracle SQL查询的结果中删除带有null sumsales列的所有行？

我试过

WHERE sumsales IS NOT NULL

上面的 GROUP BY ，但它不起作用。

用0替换null也是可以接受的，但我无法弄清楚如何在选择期间/之后替换null。

感谢您的时间。

Answer 1

由于sumsales是聚合值，因此您应使用having子句：

SELECT 
t1.aID, t1.firstname, t1.lastname,
SUM(t2.price) AS sumsales
FROM t3
  INNER JOIN t1
    ON t3.aID = t1.aID
  INNER JOIN t2
    ON t3.wID = t2.wID
GROUP BY (t1.aID, t1.firstname, t1.lastname)
HAVING sumsales IS NOT NULL
ORDER BY sumsales DESC

Answer 2

您可以使用NULL将0值替换为coalesce()：

SELECT t1.aID, t1.firstname, t1.lastname, COALESCE(SUM(t2.price), 0) AS sumsales FROM t3 INNER JOIN t1 ON t3.aID = t1.aID INNER JOIN t2 ON t3.wID = t2.wID GROUP BY t1.aID, t1.firstname, t1.lastname ORDER BY sumsales DESC;

或者，如果您不想NULL的{{1}}值，则可以在聚合之前过滤掉sumsales价格：

NULL

这通常是最有效的方法。请注意，您不能在SELECT t1.aID, t1.firstname, t1.lastname, SUM(t2.price AS sumsales FROM t3 INNER JOIN t1 ON t3.aID = t1.aID INNER JOIN t2 ON t3.wID = t2.wID WHERE t2.price IS NOT NULL GROUP BY t1.aID, t1.firstname, t1.lastname ORDER BY sumsales DESC;子句中使用聚合函数，但可以将它们放在WHERE子句中，如@NirLevy建议的那样。

除非您仅将其用于过滤目的，否则还不清楚HAVING的加入是什么。代码未使用该表中的任何列。

显示内部联接表的总和，排除NULL总和

2 个答案: