如何将一个 table 转换为另一个 table 结构并比较数据 |甲骨文

Question

我有两个具有不同结构的 table，但是 TableA 几列与 TableB 不同。这里我们必须将 TableA 转换为 TableB 结构并比较每个数据并标记 TableB 中缺失的行。如果它在 TableA 中丢失，我需要忽略此类记录。

我不想使用 Union all 并且因为我正在执行批量操作需要考虑查询性能。请建议最好的方法。

TableA

NAME	GENDER	DEPNAME	ID1	ID2	ID3	ID4	ID5
Jacob	M	Math		OfficeID	PassPort	AppID	JobID
Maria	F	Science	LabID	OfficeID	PassPort	AppID

TableB

NAME	GENDER	DEPNAME	ID
Jacob	M	Math	OfficeID
Jacob	M	Math	PassPort
Jacob	M	Math	AppID
Maria	F	Science	LabID
Maria	F	Science	OfficeID
Maria	F	Science	PassPort

Table A-B

Name	Gender	DepName	ID	MissingID
Jacob	M	Math	OfficeID	No
Jacob	M	Math	PassPort	No
Jacob	M	Math	AppID	No
Jacob	M	Math	JobID	Yes
Maria	F	Science	LabID	No
Maria	F	Science	OfficeID	No
Maria	F	Science	PassPort	No
Maria	F	Science	AppID	Yes

Answer 1

您可以对 TableA 的列的所有不同 ID 值使用条件聚合以及非透视行，例如

SELECT a.name AS "Name", a.gender AS "Gender", a.depname AS "Dept Name", a.id, 
       MIN(CASE WHEN a.id != b.id THEN 'Yes' ELSE 'No' END) AS "MissingID"
  FROM
  (
    SELECT DISTINCT *
      FROM TableA a   
   UNPIVOT (id FOR col IN ( id1 AS 'id1',
                            id2 AS 'id2',
                            id3 AS 'id3',
                            id4 AS 'id4',
                            id5 AS 'id5' ))) a
   JOIN TableB b
    ON b.name = a.name
   AND b.gender = a.gender
   AND b.depname = a.depname  
 GROUP BY a.name, a.gender, a.depname, a.id
 ORDER BY a.name, "MissingID"

Name	Gender	DepName	ID	MissingID
Jacob	M	Math	OfficeID	No
Jacob	M	Math	PassPort	No
Jacob	M	Math	AppID	No
Jacob	M	Math	JobID	Yes
Maria	F	Science	PassPort	No
Maria	F	Science	OfficeID	No
Maria	F	Science	LabID	No
Maria	F	Science	AppID	Yes

Demo

Answer 2

基本上，您想逆轴旋转 A，然后使用 LEFT JOIN 从 b:

中引入值

SELECT a.*,
       (CASE WHEN b.id IS NULL THEN 'Yes' ELSE 'No' END) as is_missing
FROM (SELECT a.name, a.gender, a.depname, i.n, i.id
      FROM TableA a CROSS JOIN LATERAL
           (SELECT 1 as n, id1 as id FROM DUAL UNION ALL
            SELECT 2 as n, id2 FROM DUAL UNION ALL
            SELECT 3 as n, id3 FROM DUAL UNION ALL
            SELECT 4 as n, id4 FROM DUAL UNION ALL
            SELECT 5 as n, id5 FROM DUAL
           ) i
      WHERE id IS NOT NULL
     ) a LEFT JOIN
     tableb b
     ON a.name = b.name AND a.gender = b.gender AND a.depname = b.depname AND a.id = b.id
ORDER BY a.name, a.gender, a.depname, a.n;

我更喜欢横向连接来取消旋转。在 Oracle 11 中，您还可以选择 unpivot。但是，更通用的方法确实使用 union all（尽管更快的方法使用 union all 和 cross join）。

请注意，不需要聚合。而且这个 returns id 按照它们在 A.

中出现的顺序排列

Here 是一个 db<>fiddle.

如何将一个 table 转换为另一个 table 结构并比较数据 |甲骨文

How to convert one table to another table structure and compare data | Oracle

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