Question

有人可以在下面的查询中看到我出错的地方吗？我收到GROUP BY列不存在的错误消息，但是当我不使用GROUP BY时，我在输出中看到列名时显然会这样做。

SELECT
           (SELECT customer_address.post_code FROM customer_address WHERE customer_address.address_type = 0 AND customer_address.customer_no = orders.customer_no) postcode, SUM(orders.order_no) orders
FROM
           orders, customer_address
WHERE
           orders.delivery_date = '27-MAY-15'
GROUP BY
           postcode;

Answer 1

答案是：您不能在GROUP BY中使用别名。

所以：

GROUP BY (SELECT customer_address.post_code ...);

或者：

select postcode, sum(order_no)
from
(
  SELECT
    (SELECT customer_address.post_code FROM customer_address WHERE customer_address.address_type = 0 AND customer_address.customer_no = orders.customer_no) postcode, 
    orders.order_no
  FROM orders, customer_address
  WHERE orders.delivery_date = '27-MAY-15'
)
GROUP BY postcode;

编辑：

但是，您的查询似乎有误。为什么要交叉加入订单和customer_address？我猜错了。使用连接时使用显式连接（INNER JOIN customer_address ON ...）以避免此类错误。但在这里，我猜您只需删除, customer_address。

那为什么要添加订单号？这似乎没有意义。

ORA-00904：列名无效，但我使用的是正确的列名

1 个答案: