将SQL语句更改为EXISTS子句

Question

给出以下SQL状态：

select 
    OBJECT_ID
FROM HPSFWY.RVERSIONING_1703 A 
WHERE A.STAMP_ID >1 
    AND A.OBJECT_REV NOT IN (
select MAX(OBJECT_REV)
from HPSFWY.RVERSIONING_1709763 B 
where B.COMMITID <= 6066 
    and B.OBJECT_ID = A.OBJECT_ID 
    ) 

在此查询中，where子句AND OBJECT_REV NOT IN必须从NOT IN更改为等效的EXISTS语句。

我们尝试这个

select 
OBJECT_ID
FROM HPSFWY.RVERSIONING_1703 A 
WHERE A.STAMP_ID >1 
AND exists (
select * 
from HPSFWY.RVERSIONING_1709763 B 
where B.COMMITID <= 6066 
and B.OBJECT_ID = A.OBJECT_ID 
and B.OBJECT_REV > A.OBJECT_REV) ;

它给我们带来接近的结果，但不尽相同

Answer 1

您可以使用NOT EXISTS这样操作：

SELECT A.OBJECT_ID
FROM HPSFWY.RVERSIONING_1703 A 
WHERE 
  A.STAMP_ID > 1 
  AND 
  NOT EXISTS (
    SELECT 1 FROM (
      SELECT MAX(B.OBJECT_REV) MAXOBJECT_REV
      FROM HPSFWY.RVERSIONING_1709763 B 
      WHERE B.COMMITID <= 6066 AND B.OBJECT_ID = A.OBJECT_ID 
    ) t
    WHERE t.MAXOBJECT_REV = A.OBJECT_REV
  )

注意：NOT IN的子查询：
select MAX(OBJECT_REV)
from HPSFWY.RVERSIONING_1709763 B 
where B.COMMITID <= 6066 and B.OBJECT_ID = A.OBJECT_ID 

仅返回1行和1列。因此，您可以像这样使用NOT IN代替<>：
SELECT A.OBJECT_ID
FROM HPSFWY.RVERSIONING_1703 A 
WHERE 
  A.STAMP_ID > 1 
  AND 
  A.OBJECT_REV <> (
    SELECT MAX(OBJECT_REV)
    FROM HPSFWY.RVERSIONING_1709763 B 
    WHERE B.COMMITID <= 6066 AND B.OBJECT_ID = A.OBJECT_ID 
  )