使用 SQL 在数据库 table 中查找不存在匹配键的匹配行

Question

我有一个包含遗留数据和大约 10,000 行的旧 table 和一个包含大约 500 行的新 table。两个 table 中的列相同。我需要将新 table 中的几列与旧列进行比较，并报告新 table.

中重复的数据

我研究了具有类似问题的文章，尝试了 table 连接和 where exists / where not exists 子句，但我无法正确地 SQL。我已经包含了我的最新版本。

我认为给我带来麻烦的一个问题是 table.

中没有像用户 ID 或类似唯一标识符这样的“密钥”

我想要做的是在“新”table 中找到数据，其中除“reference_number”（不管是否存在）之外的所有行都是重复，即已经存在于“旧”table.

到目前为止我有这个...

select 
old.reference_number
new.reference_number
new.component
new.privileges
new.protocol
new.authority
new.score
new.means
new.difficulty
new.hierarchy
new.interaction
new.scope
new.conf
new.integrity
new.availability
new.version
from old, new
where
old.component = new.component
old.privileges = new.privileges
old.protocol = new.protocol
old.authority = new.authority
old.score = new.score
old.means = new.means
old.difficulty = new.difficulty
old.hierarchy = new.hierarchy
old.interaction = new.interaction
old.scope = new.scope
old.conf = new.conf
old.integrity = new.integrity
old.availability = new.availability
old.version = new.version

我在这里试过了，但由于某种原因它似乎没有提取所有数据。

很明显，旧 table 中实际上有更多行在新 table 中重复，但我只从查询中返回少量行。

任何人都可以找出为什么会这样吗，还有其他方法可以解决这个问题吗？

如果重要的话，这是 Postgresql。

感谢您提供的任何帮助。

Answer 1

下面应该做你想做的：

select distinct o.reference_number,
                n.reference_number,
                n.component,
                n.privileges,
                n.protocol,
                n.authority,
                n.score,
                n.means,
                n.difficulty,
                n.hierarchy,
                n.interaction,
                n.scope,
                n.conf,
                n.integrity,
                n.availability,
                n.version
  from new n
  inner join old o
    on o.component = n.component and
       o.privileges = n.privileges and
       o.protocol = n.protocol and
       o.authority = n.authority and
       o.score = n.score and
       o.means = n.means and
       o.difficulty = n.difficulty and
       o.hierarchy = n.hierarchy and
       o.interaction = n.interaction and
       o.scope = n.scope and
       o.conf = n.conf and
       o.integrity = n.integrity and
       o.availability = n.availability and
       o.version = n.version

Answer 2

您应该使用左联接，然后 select 只有具有新值的行为空。 sql 应该是这样的：

select 
old.reference_number
new.reference_number
new.component
new.privileges
new.protocol
new.authority
new.score
new.means
new.difficulty
new.hierarchy
new.interaction
new.scope
new.conf
new.integrity
new.availability
new.version
from old 
  left join new
  on
old.component = new.component
old.privileges = new.privileges
old.protocol = new.protocol
old.authority = new.authority
old.score = new.score
old.means = new.means
old.difficulty = new.difficulty
old.hierarchy = new.hierarchy
old.interaction = new.interaction
old.scope = new.scope
old.conf = new.conf
old.integrity = new.integrity
old.availability = new.availability
old.version = new.version
where new.component is null

使用 SQL 在数据库 table 中查找不存在匹配键的匹配行

Find matching rows in database table using SQL where no matching key is present

sql

postgresql