JOIN别名不存在且未正确结束

Question

正如this线程中所讨论的那样，from子句中的子查询不是必需的并且会产生笛卡尔积，但会出现新的问题。

SELECT customer.customer_name
       ,orders.order_date
       ,order_line.num_ordered
       ,order_line.quoted_price
       ,part.descript
       ,amt_billed
FROM   (SELECT order_line.num_ordered*part.price AS amt_billed
          FROM order_line
          JOIN part
            ON order_line.part_num = part.part_num
          ) billed
           ,customer
      JOIN orders
        ON customer.customer_num = orders.customer_num
      JOIN order_line
        ON orders.order_num = order_line.order_num
      JOIN part
        ON order_line.part_num = part.part_num;

让我们说我决定在from子句中使用子查询。如果您阅读了注释，@ GeorgeCampos建议我使用AS建立别名，然后在子查询和现有表之间编写连接。

当我在子查询和别名AS之间放置billed时，我得到ORA-00933: SQL command not properly ended。删除AS并运行它不会返回错误，但会返回笛卡尔积。

此外，我尝试使用join别名的任何billed都会返回ORA-00942: table or view does not exist。

为了便于参考，这里是整个数据库的ERD：

总之，如果我决定将子查询保留在from子句中，我想知道如何写这个。

我使用的是Oracle 11g pl / sql。

更新

此：

SELECT customer.customer_name
       ,orders.order_date
       ,order_line.num_ordered
       ,order_line.quoted_price
       ,part.descript
       ,amt_billed
FROM (SELECT order_line.num_ordered*part.price AS amt_billed, orders.order_num
        FROM order_line
        JOIN part
          ON order_line.part_num = part.part_num
           ) AS billed
    JOIN customer
      ON customer.customer_num = orders.customer_num
    JOIN billed
      ON orders.order_num = order_line.order_num
    JOIN orders
      ON customer.customer_num = orders.customer_num
    JOIN order_line
      ON orders.order_num = order_line.order_num
    JOIN part
      ON order_line.part_num = part.part_num;

返回：

       ) AS billed
         *
ERROR at line 11:
ORA-00933: SQL command not properly ended

在第11行删除AS会返回：

JOIN billed
     *
ERROR at line 14:
ORA-00942: table or view does not exist

更新

感谢@GordonLinoff，我向您呈现最终代码！

SELECT customer.customer_name
       ,orders.order_date
       ,order_line.num_ordered
       ,order_line.quoted_price
       ,amt_billed
       ,part.descript
  FROM customer
    JOIN orders
      ON customer.customer_num = orders.customer_num
    JOIN order_line
      ON orders.order_num = order_line.order_num
    JOIN part
      ON order_line.part_num = part.part_num
    JOIN (SELECT DISTINCT order_line.part_num
                          ,order_line.num_ordered*part.price AS amt_billed
            FROM order_line
            JOIN part
              ON order_line.part_num = part.part_num
        ) billed
      ON billed.part_num = order_line.part_num
ORDER BY customer.customer_name, orders.order_date;

我按照他说的做了，并删除了对客户的冗余连接。我还必须换掉子选择的内容。如果我坚持使用num_ordered，只要订购了一个零件，行就会重复自己。

Answer 1

Oracle不支持as表别名。所以：

FROM (SELECT order_line.num_ordered*part.price AS amt_billed, orders.order_num
      FROM order_line JOIN
           part
           ON order_line.part_num = part.part_num
      ) billed JOIN
--------^
      Customer
      . . .

编辑：

您不需要重复 billed。你想要这样的东西：

FROM customer JOIN
     orders
     ON customer.customer_num = orders.customer_num JOIN
     order_line
     ON orders.order_num = order_line.order_num JOIN
     part
     ON order_line.part_num = part.part_num JOIN
     (SELECT order_line.order_num, order_line.num_ordered*part.price AS amt_billed
      FROM order_line JOIN
           part
           ON order_line.part_num = part.part_num
     ) billed
     ON billed.order_num = order.order_num;