问使用某些标准的where子句，server 2005似乎要花费很长时间。

EN

[dbo].[Action_History](
    [ActionID] [int] IDENTITY(1,1) NOT NULL,
    [objectID] [int] NOT NULL,
    [object_mask] [varchar](max) NULL,
    [description] [varchar](max) NOT NULL,
    [action_by] [nchar](7) NOT NULL,
    [action_date] [datetime] NOT NULL,
    [response_required] [bit] NOT NULL,
    [responded_date] [datetime] NULL,
    [responded_by] [nchar](7) NULL,
    [recurring] [bit] NULL CONSTRAINT [DF_Action_History_recurring]  DEFAULT ((0)),
    [actionTypeID] [int] NULL,
    [target_user] [nchar](7) NULL,
    [target_role] [varchar](25) NULL,
    [object_type] [varchar](30) NULL, CONSTRAINT [PK_Action_History] PRIMARY KEY CLUSTERED 

SELECT    
    Top(1) 
    ActionID, objectID, object_mask, 
    [description], action_by, action_date, response_required, 
    responded_date, responded_by, recurring, actionTypeID, 
    target_user, target_role, object_type
FROM
    Action_History
WHERE     
    ((objectID = 201006)
    AND (responded_date is null)    
    AND (object_type = 'MyType'))

SELECT    
    Top(1) 
    ActionID, objectID, object_mask, 
    [description], action_by, action_date, response_required, 
    responded_date, responded_by, recurring, actionTypeID, 
    target_user, target_role, object_type
FROM
    Action_History
WHERE     
    ((objectID = 201006)
    AND (responded_date is null)    
    AND (object_type = 'Mytype')
    AND (actionTypeID = 55) 
    AND (response_required = 1))

  |--Top(TOP EXPRESSION:((1)))
       |--Clustered Index Scan(OBJECT:([db].[dbo].[Action_History].[PK_Action_History]), 
                                WHERE:([db].[dbo].[Action_History].[objectID]=(201002) AND 
                                       [db].[dbo].[Action_History].[responded_date] IS NULL AND 
                                       [db].[dbo].[Action_History].[actionTypeID]=(55) AND 
                                       [db].[dbo].[Action_History].[response_required]=(1) AND 
                                       [db].[dbo].[Action_History].[object_type]='MyType'))