Question

我在以下msdn主题中看到过这种类型的UPDATE语句（就像插入语句一样）：

http://msdn.microsoft.com/en-us/library/aa0416cz.aspx#Y2461

更新声明： -

adapter.UpdateCommand = New SqlCommand("UPDATE Customers " &
  "(CustomerID, CompanyName) VALUES(@CustomerID, @CompanyName) " & _
  "WHERE CustomerID = @oldCustomerID AND CompanyName = " &
  "@oldCompanyName", connection)

这个陈述是否正确？

我尝试过执行它，但是它会出现语法错误。

Answer 1

不，应该是：

UPDATE Customers
SET 
CustomerID = @CustomerID,
CompanyName = @CompanyName
WHERE
CustomerID = @oldCustomerID AND
CompanyName = @oldCompanyName

或者要完成示例代码，它应该是：

adapter.UpdateCommand = New SqlCommand("UPDATE Customers SET CustomerID = @CustomerID, CompanyName = @CompanyName WHERE CustomerID = @oldCustomerID AND CompanyName = @oldCompanyName", connection)

以下是您和此情况的另一个参考：http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqldataadapter.updatecommand.aspx

Answer 2

对于INSERT INTO而言，SQL似乎是正确的，而对于UPDATE则不正确它应该是：

adapter.UpdateCommand = New SqlCommand("UPDATE Customers" & _
    " SET CustomerID = @CustomerID, CompanyName = @CompanyName)" & _
    " WHERE CustomerID = @oldCustomerID AND CompanyName =" & _
    " @oldCompanyName", connection)

SQL就是人们称之为paramaterized的东西，因此这段代码（在代码片段中较低）非常重要：

adapter.UpdateCommand.Parameters.Add( _
  "@CustomerID", SqlDbType.NChar, 5, "CustomerID")
adapter.UpdateCommand.Parameters.Add( _
  "@CompanyName", SqlDbType.NVarChar, 30, "CompanyName")

' Pass the original values to the WHERE clause parameters.
Dim parameter As SqlParameter = dataSet.UpdateCommand.Parameters.Add( _
  "@oldCustomerID", SqlDbType.NChar, 5, "CustomerID")
parameter.SourceVersion = DataRowVersion.Original
parameter = adapter.UpdateCommand.Parameters.Add( _
  "@oldCompanyName", SqlDbType.NVarChar, 30, "CompanyName")
parameter.SourceVersion = DataRowVersion.Original

Answer 3

据我所知，语法无效。以下内容为Incorrect syntax near '('.

我建议按照Dan's answer进行更改。

CREATE TABLE Customers
(
CustomerID INT, 
CompanyName VARCHAR(10)
)

DECLARE 
@CustomerID INT, 
@CompanyName VARCHAR(10),
@oldCustomerID INT,
@oldCompanyName VARCHAR(10)

UPDATE Customers  (CustomerID, CompanyName)
VALUES(@CustomerID, @CompanyName)
WHERE CustomerID = @oldCustomerID AND CompanyName = @oldCompanyName

这个UPDATE表语句在msdn主题中是否正确

3 个答案: