Question

我的任务之一是将访问SQL转换为Oracle SQL。我在MS访问中运行查询，这是关系表，查询SQL和查询结果： Query Design

Query result

访问查询SQL

SELECT PUBLISHER.PUBLISHER_CODE, PUBLISHER.PUBLISHER_NAME, BOOK.TITLE, BOOK.TYPE, INVENTORY.BRANCH_NUM, BRANCH.BRANCH_NAME
FROM PUBLISHER INNER JOIN (BRANCH INNER JOIN (BOOK INNER JOIN INVENTORY ON BOOK.BOOK_CODE = INVENTORY.BOOK_CODE) ON BRANCH.BRANCH_NUM = INVENTORY.BRANCH_NUM) ON PUBLISHER.PUBLISHER_CODE = BOOK.PUBLISHER_CODE
WHERE (((BOOK.TYPE)='FIC') AND ((BRANCH.BRANCH_NAME)='Henry on the Hill'))
ORDER BY PUBLISHER.PUBLISHER_NAME;

认为MS SQL可能在oracle中工作，我试过了：

SQL> SELECT PUBLISHER.PUBLISHER_CODE, PUBLISHER.PUBLISHER_NAME, BOOK.TITLE, BOOK.TYPE, INVENTORY.BRANCH_NUM, BRANCH.BRANCH_NAME
  2  FROM PUBLISHER INNER JOIN (BRANCH INNER JOIN (BOOK INNER JOIN INVENTORY ON BOOK.BOOK_CODE = INVENTORY.BOOK_CODE) ON BRANCH.BRANCH_NUM = INVENTORY.BRANCH_NUM) ON PUBLISHER.PUBLISHER_CODE = BOOK.PUBLISHER_CODE
  3  WHERE (((BOOK.TYPE)='FIC') AND ((BRANCH.BRANCH_NAME)='Henry on the Hill'))
  4  ORDER BY PUBLISHER.PUBLISHER_NAME;

no rows selected

显然没有用。所以，我有点切入/粘贴/编辑我的oracle 11g。这就是我得到的：

SQL> SELECT PUBLISHER.PUBLISHER_CODE, PUBLISHER.PUBLISHER_NAME, BOOK.TITLE, BOOK.TYPE,
  2   INVENTORY.BRANCH_NUM, BRANCH.BRANCH_NAME
  3  FROM PUBLISHER
  4   inner join BOOK  ON PUBLISHER.PUBLISHER_CODE = BOOK.PUBLISHER_CODE
  5  inner join INVENTORY on INVENTORY.BRANCH_NUM = BRANCH.BRANCH_NUM
  6  inner join BRANCH on INVENTORY.BRANCH_NUM = BRANCH.BRANCH_NUM
  7   where BOOK.BOOK_TYPE = 'FIC'
  8   and BRANCH.BRANCH_NAME = 'Henry on the Hill';
inner join INVENTORY on INVENTORY.BRANCH_NUM = BRANCH.BRANCH_NUM
                                               *
ERROR at line 5:
ORA-00904: "BRANCH"."BRANCH_NUM": invalid identifier

为什么我得到这个：第5行的错误： ORA-00904：“BRANCH”。“BRANCH_NUM”：标识符无效

联接订单会影响吗？正如你所看到的，我确实从一个表到另一个表。

语法顺序有问题吗？ EX：

INVENTORY.BRANCH_NUM = BRANCH.BRANCH_NUM上的内连接BRANCH 或 BRANCH.BRANCH_NUM = INVENTORY.BRANCH_NUM

的内连接BRANCH

这有关系吗？

Oracle SQL中的连接是否按正确顺序正确格式化？

如果是这样，为什么不运行？

旁注，这是一个在线课程，虽然讲师非常专注，但我在这里学到了很多东西，从阅读其他帖子，并问自己的问题。谢谢大家！

Answer 1

加入顺序很重要，例如check this answer。您无法访问条件之前未引入的表别名，例如您无法在第5行访问BRANCH，因为它仅在下一个联接中引入。

来自MS Access的代码引入了很多括号来限制加入顺序。只需对其应用格式并查看结果：

SELECT
  PUBLISHER.PUBLISHER_CODE,
  PUBLISHER.PUBLISHER_NAME,
  BOOK.TITLE,
  BOOK.TYPE,
  INVENTORY.BRANCH_NUM,
  BRANCH.BRANCH_NAME
FROM
  PUBLISHER
  INNER JOIN (
    BRANCH INNER JOIN (
      BOOK INNER JOIN INVENTORY
        ON BOOK.BOOK_CODE = INVENTORY.BOOK_CODE
      )
      ON BRANCH.BRANCH_NUM = INVENTORY.BRANCH_NUM
    )
    ON PUBLISHER.PUBLISHER_CODE = BOOK.PUBLISHER_CODE
WHERE
  (
    (
      (BOOK.TYPE)='FIC'
    )
    AND
    (
      (BRANCH.BRANCH_NAME)='Henry on the Hill'
    )
  )
ORDER BY
  PUBLISHER.PUBLISHER_NAME

删除不需要的括号后，如下所示：

SELECT
  PUBLISHER.PUBLISHER_CODE,
  PUBLISHER.PUBLISHER_NAME,
  BOOK.TITLE,
  BOOK.TYPE,
  INVENTORY.BRANCH_NUM,
  BRANCH.BRANCH_NAME
FROM
  PUBLISHER
  INNER JOIN BRANCH
  INNER JOIN BOOK
  INNER JOIN INVENTORY
             ON BOOK.BOOK_CODE = INVENTORY.BOOK_CODE
                AND
                BRANCH.BRANCH_NUM = INVENTORY.BRANCH_NUM
                AND
                PUBLISHER.PUBLISHER_CODE = BOOK.PUBLISHER_CODE
WHERE
  BOOK.TYPE='FIC'
  AND
  (BRANCH.BRANCH_NAME = 'Henry on the Hill')
ORDER BY
  PUBLISHER.PUBLISHER_NAME

看起来更好，但仅通过将ANSI语法转换为普通查询就可以避免排序问题：
警告：ANSI语法，请不要阅读此答案的其余部分： - ）

SELECT
  PUBLISHER.PUBLISHER_CODE,
  PUBLISHER.PUBLISHER_NAME,
  BOOK.TITLE,
  BOOK.TYPE,
  INVENTORY.BRANCH_NUM,
  BRANCH.BRANCH_NAME
FROM
  PUBLISHER,
  BRANCH,
  BOOK,
  INVENTORY
WHERE
  BOOK.TYPE='FIC'
  AND
  (BRANCH.BRANCH_NAME = 'Henry on the Hill')
  AND
  PUBLISHER.PUBLISHER_CODE = BOOK.PUBLISHER_CODE
  AND
  BOOK.BOOK_CODE = INVENTORY.BOOK_CODE
  AND
  BRANCH.BRANCH_NUM = INVENTORY.BRANCH_NUM
ORDER BY
  PUBLISHER.PUBLISHER_NAME

通过这种变体，条件的顺序无关紧要，并且所有条件都放在一起，因此可以按逻辑顺序重新组织它：

SELECT
  PUBLISHER.PUBLISHER_CODE,
  PUBLISHER.PUBLISHER_NAME,
  BOOK.TITLE,
  BOOK.TYPE,
  INVENTORY.BRANCH_NUM,
  BRANCH.BRANCH_NAME
FROM
  BRANCH,
  INVENTORY,
  BOOK,
  PUBLISHER
WHERE
  (BRANCH.BRANCH_NAME = 'Henry on the Hill') -- start from most restrictive 
                                             -- condition (concrete branch)  
  AND
  INVENTORY.BRANCH_NUM = BRANCH.BRANCH_NUM   -- get all inventory from this branch
  AND
  BOOK.BOOK_CODE = INVENTORY.BOOK_CODE       -- access book specification 
                                             -- corresponding to inventory
  AND    
  BOOK.TYPE = 'FIC'                          -- of specific type 
  AND
  PUBLISHER.PUBLISHER_CODE = BOOK.PUBLISHER_CODE  -- and finally find 
                                                  -- all publishers of that books
ORDER BY
  PUBLISHER.PUBLISHER_NAME

因此，在最后一个变体中，可以以人类可读的格式再现查询逻辑请注意，查询文本中表的顺序（至少在Oracle中如果不使用某些特殊提示）不会影响实际查询执行计划，因为优化程序会根据需要自行更改它。因此，在大多数情况下，ANSI变体只是在没有真正帮助的情况下引入语法限制。

Answer 2

您的原始查询加入了INVENTORY，如下所示：

inner join INVENTORY ON BOOK.BOOK_CODE = INVENTORY.BOOK_CODE

试试这个：

select PUBLISHER.PUBLISHER_CODE, PUBLISHER.PUBLISHER_NAME, BOOK.TITLE, BOOK.TYPE, INVENTORY.BRANCH_NUM, BRANCH.BRANCH_NAME
from PUBLISHER
inner join BOOK on PUBLISHER.PUBLISHER_CODE = BOOK.PUBLISHER_CODE
inner join INVENTORY on BOOK.BOOK_CODE = INVENTORY.BOOK_CODE
inner join BRANCH on BRANCH.BRANCH_NUM = INVENTORY.BRANCH_NUM
where BOOK.TYPE = 'FIC'
    and BRANCH.BRANCH_NAME = 'Henry on the Hill'
order by PUBLISHER.PUBLISHER_NAME;

SQL - 理解'JOIN'语法，顺序

2 个答案: