在SQL Server上僅刪除一條記錄

Question

假定在SQL Server上有一個表EMPLOYEE ，其列ID (int), Name (nvarchar), Surname(nvarchar) 。

這就是您所知道的。 您無法在表格內看到數據。

您被命令僅刪除名稱為“ Alice”的一條記錄。

您將如何編寫適當的查詢？

Answer 1

DELETE TOP (1)
FROM EMPLOYEE 
WHERE Name='Alice'

Answer 2

DELETE TOP (1) FROM EMPLOYEE WHERE Name = 'Alice'

Answer 3

在SQL Server中：

DELETE TOP 1 FROM EMPLOYEE WHERE Name = 'Alice'

Answer 4

此處建議的所有答案基本上都是相似的，就您介紹問題而言，它們都是最佳的。

但這將迫使您的代碼刪除Name ='Alice'的第一條記錄。 但是，如果您需要一點額外的權力來選擇要刪除的“愛麗絲”（如果表中有多個）。 但是ID必須是Primary Key或Unique

SELECT FROM EMPLOYEE ID, Surname WHERE Name = 'Alice'

這將顯示結果，然后您可以獲取要刪除的目標記錄的ID並將其放在以下查詢中（假設您要刪除的記錄的ID為56）

DELETE FROM EMPLOYEE  WHERE ID = 56

Answer 5

declare @Holder table ( EmployeeKey int , Name varchar(24) , Surname varchar(24) )


Insert into @Holder ( EmployeeKey , Name , Surname )
            select 201 , 'Alice' , 'Smith'
union all   select 102 , 'Mary' , 'Smith'
union all   select 203 , 'Alice' , 'Henderson'
union all   select 104 , 'John' , 'Smith'
union all   select 105 , 'Paul' , 'Johnson'
union all   select 206 , 'Alice' , 'Jones'

Delete @Holder
/*  Select * ............. while debugging, you can remove the 'Delete @Holder' and put in a 'Select *' to see the results (of what ~will be deleted) */
From 
@Holder h
join 
(select top 1 EmployeeKey from @Holder innerH where Name = 'Alice' /* order by EmployeeKey DESC */ ) as derived1
 on h.EmployeeKey = derived1.EmployeeKey

select * from @Holder order by Name , EmployeeKey

/*
order by EmployeeKey DESC is optional, aka, if you want to "prefer" which one gets popped for delete, you can tweak it as needed
*/