Question

在SQL查询中，Oracle中是否有任何方法可以从其外部的子查询中引用列，或者即使通过不同的方式实现该效果？到目前为止，我在网上看到的所有内容都没有帮助。

例如（这是我想要的事情）：

SELECT a.product_code, b.received, b.issued
FROM productinfo a,
 (SELECT SUM(qty_received) AS received, SUM(qty_issued) AS issued
  FROM productdetail b WHERE b.product_code = a.product_code AND active = 1);

我尝试了大量不同的变体/组合当我遇到像ORA-00904这样的错误：与WHERE子句关系有关的无效标识符。

目前，如果我作为单独的查询运行，例如：

SELECT product_code FROM productinfo;

然后对于每个记录：

SELECT SUM(qty_received) AS received, SUM(qty_issued) AS issued FROM productdetail
WHERE product_code = '(specified)' AND active = 1;

这可能需要半个多小时来运行8000条记录，这些记录只是简单的愚蠢。

头发耗尽，任何帮助都赞赏!!谢谢。

Answer 1

ORA错误是因为您无法关联派生表/内联视图 - 您需要使用JOIN表示法（ANSI-89或92）。

假设您确实需要PRODUCTINFO表中的列，请使用：

SELECT a.product_code, b.received, b.issued
  FROM PRODUCTINFO a
  JOIN (SELECT t.product_code,
               SUM(t.qty_received) AS received, 
               SUM(t.qty_issued) AS issued
          FROM PRODUCTDETAIL t 
         WHERE t.active = 1
      GROUP BY t.produce_code) b ON b.product_code = a.product_code

如果您想查看productinfo记录的列表，可能有也可能没有PRODUCTDETAIL记录，请使用：

   SELECT a.product_code, b.received, b.issued
     FROM PRODUCTINFO a
LEFT JOIN (SELECT t.product_code,
                  SUM(t.qty_received) AS received, 
                  SUM(t.qty_issued) AS issued
             FROM PRODUCTDETAIL t 
            WHERE t.active = 1
         GROUP BY t.produce_code) b ON b.product_code = a.product_code

但是示例看起来您可能只需要使用：

 SELECT t.product_code,
        SUM(t.qty_received) AS received, 
        SUM(t.qty_issued) AS issued
   FROM PRODUCTDETAIL t 
   WHERE t.active = 1
GROUP BY t.produce_code

Answer 2

只需在查询中分组并使用内部联接

SELECT a.product_code, b.received, b.issued
FROM productinfo a
INNER JOIN
 (SELECT product_code, SUM(qty_received) AS received, SUM(qty_issued) AS issued
  FROM productdetail
  WHERE active = 1
  GROUP BY product_code) b on b.product_code = a.product_code

优化SQL语句以使用查询但需要以某种方式引用子查询之外的列

2 个答案: