请帮忙解决update语句错误？
我的是access数据库，检查了很多次，还是提示错误？请高手帮忙解决？
提示：---------------------------

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UPDATE 语句的语法错误。
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确定  
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代码如下：
OleDbCommand UpdateCommand = new OleDbCommand();
  UpdateCommand.Connection = connection;
  string updatesql = "update from zhangdan set CustomerID=@CustomerID,DeviceName=@DeviceName,count=@count,UnitPrice=@UnitPrice,AllUnitPrice=@AllUnitPrice,DataTime=@DataTime where ID=@ID";
  UpdateCommand.CommandText = updatesql;

  UpdateCommand.Parameters.Add("@CustomerID", OleDbType.Integer, 4, "CustomerID");
  UpdateCommand.Parameters.Add("@DeviceName", OleDbType.VarChar, 20, "DeviceName");
  UpdateCommand.Parameters.Add("@count", OleDbType.Integer, 4, "count");
  UpdateCommand.Parameters.Add("@UnitPrice", OleDbType.VarChar, 20, "UnitPrice");
  UpdateCommand.Parameters.Add("@AllUnitPrice", OleDbType.VarChar, 20, "AllUnitPrice");
  UpdateCommand.Parameters.Add("@DataTime", OleDbType.DBTimeStamp, 20, "DataTime");
  UpdateCommand.Parameters.Add("@ID", OleDbType.Integer, 4, "ID");
  adapter.UpdateCommand = UpdateCommand;

------解决方案--------------------
OleDbCommand UpdateCommand = new OleDbCommand();
UpdateCommand.Connection = connection;
string updatesql = "update from zhangdan set CustomerID=?,DeviceName=?,count=?,UnitPrice=?,AllUnitPrice=?,DataTime=? where ID=?";
UpdateCommand.CommandText = updatesql;

UpdateCommand.Parameters.Add("?", OleDbType.Integer, 4, "CustomerID");
UpdateCommand.Parameters.Add("?", OleDbType.VarChar, 20, "DeviceName");
UpdateCommand.Parameters.Add("?", OleDbType.Integer, 4, "count");
UpdateCommand.Parameters.Add("?", OleDbType.VarChar, 20, "UnitPrice");
UpdateCommand.Parameters.Add("?", OleDbType.VarChar, 20, "AllUnitPrice");
UpdateCommand.Parameters.Add("?", OleDbType.DBTimeStamp, 20, "DataTime");
UpdateCommand.Parameters.Add("?", OleDbType.Integer, 4, "ID");
adapter.UpdateCommand = UpdateCommand;
------解决方案--------------------
都没有给各个变量赋值。