SQL删除唯一行表

Question

我有如下表：

PatientID | DiagID 

...其中PatientID是一个唯一的标识符，DiagID是诊断ID，这是不是唯一的。我如何从表格中删除患者，谁拥有独特的DiagID（表中唯一的人，谁拥有这个具体的DiagID）？

Answer 1

假定您想要删除任何只有单个诊断ID实例的患者。在这种情况下，SQL将如下所示：

DELETE Patient 
WHERE DiagID in 
(SELECT DiagID FROM Patient GROUP BY DiagID HAVING COUNT(*) = 1) 

Answer 2

一个删除where子句没有使用主键，例如：

Delete From Table 
Where DiagID = 5 

如果你的意思是你要删除所有不重复则是这样的：

Delete From Table 
Where DiagID In (Select DiagID 
       From Table 
       Group By DiagID 
       HAVING count(*) = 1) 

Answer 3

你说只有一名患者具有此特定诊断ID？

delete 
from YourTable 
where DiagID = @diagId 

Answer 4

如果你知道它是唯一一个那么有没有错

DELETE FROM Patient 
WHERE DiagID = @inDiagID 

如果你想成为安全，这样的事情也许是明智的：

IF NOT EXISTS(SELECT DiagID FROM Patient WHERE DiagID = @inDiagID GROUP BY DiagID HAVING COUNT(DiagID) = 1) 
BEGIN 
     DELETE FROM Patient 
     WHERE DiagID = @inDiagID 
END 

Answer 5

您是否尝试删除只有一个DiagID的患者？

DELETE FROM table 
    WHERE PatientID IN 
    (SELECT DiagID FROM table 
    GROUP BY DiagID 
    HAVING COUNT(*) = 1) 

Answer 6

DELETE 
    D 
FROM 
    DiagTable D 
    JOIN 
    (SELECT DiagID FROM DiagTable D2 GROUP BY DiagID HAVING COUNT(*) = 1) foo ON D.DiagID = foo.DiagID 

子查询找到独特的（即使用一次）DiagIDs。这用于JOIN bak删除这些唯一DiagID的行