Mysql SQL-理解'；加入'；语法、顺序

我的任务之一是将access SQL转换为Oracle SQL。 我在MS access中运行了查询，下面是关系表、查询SQL和查询结果：

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;

考虑到MS SQL可能在oracle中工作，我尝试了：

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，这不起作用。 所以，我在我的Oracle11g中做了一些剪切/粘贴/编辑的事情。以下是我得到的：

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

那么为什么我会得到这个： 第5行错误： ORA-00904：“分支”。“分支编号”：无效标识符

连接的顺序会影响什么吗？ 正如你们所看到的，我确实按顺序从一张桌子转到另一张桌子

语法顺序重要吗？例：

INVENTORY.BRANCH\u NUM=BRANCH.BRANCH\u NUM上的内部联接分支 或 BRANCH.BRANCH\u NUM=INVENTORY.BRANCH\u NUM上的内部联接分支

那有关系吗

Oracle SQL中的联接是否按照正确的顺序正确格式化

如果是这样，为什么它不运行

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旁注，这是一个在线课程，虽然讲师非常专注，但我从阅读其他帖子和问我自己的问题中学到了很多。谢谢大家

您的原始查询如下所示：

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;

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例如，连接顺序很重要。您无法访问在条件之前未引入的表别名，例如，您无法访问第5行的分支，因为它仅在下一个联接中引入

来自MS Access的代码引入了许多括号来限制联接顺序。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

移除不需要的支架后，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，但只要将ANSI语法转换为普通查询，就可以避免排序问题：
警告：ANSI语法funs，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

由于条件的变化顺序无关紧要，所有条件都放在一起，因此可以按逻辑顺序重新组织：

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，在最后一种变体中，可以以人类可读的格式再现查询逻辑。

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请注意，查询文本中表的顺序（至少在Oracle中，如果您不使用一些特殊提示的话）不会影响真正的查询执行计划，因为优化器会根据需要自行更改它。因此，在大多数情况下，ANSI variant只是引入语法限制，没有真正的帮助。

我仍然得到“未选择行”，这对我来说没有意义。如果您提供一些示例数据和模式，我可以进一步帮助您。您的语句“因此ANSI variant在大多数情况下只是引入语法限制，而没有真正的帮助”听起来像是您已经证明的东西，但据我所知，您确实没有。IMO ANSI查询语法在可读性和清晰性方面要好得多，更具自文档性（如预期的联接类型），并且更能防止联接中的错误（如缺少联接），这是您的方法永远无法捕捉到的。除此之外，我发现您的格式更难阅读，并且有多余的注释，例如“对应于清单”，这些注释在ANSI语法中非常清楚。@RedFilter似乎在答案的中间遗漏了一条警告：）不同的人有不同的笔划。因此，国际海事组织对这两种观点来说都是最好的资格。