如何在SQL Server 2005中更正此查询

Question

我有一个查询，它是两个查询的并集，结果查询返回重复记录，我不想重复记录。 我尝试使用DISTINCT但仍得到相同的结果，有人可以帮助我解决此查询吗？

我还想知道此查询对SQL注入是否安全...我将在下面粘贴我的查询：

ALTER PROCEDURE [dbo].[sp_GetTrashListWithSorting] --'6dbf9a01-c88f-414d-8dd9-696749258cef', '6dbf9a01-c88f-414d-8dd9-696749258cef','DateTime ASC','0','30'
(
    @p_CreatedBy UNIQUEIDENTIFIER,
    @p_ToReceipientID UNIQUEIDENTIFIER,
    @p_SortExpression NVARCHAR(100),
    @p_StartIndex INT,
    @p_MaxRows INT
)
AS
    SET NOCOUNT ON;

    IF LEN(@p_SortExpression) = 0 
       SET @p_SortExpression ='DateTime DESC'

    DECLARE @Sql NVARCHAR(4000)

    SET @sql = 'SELECT ID, DateTime, Subject, CreatedBy, ToReceipientID, Status
                FROM (SELECT ID, 
                             DateTime, 
                             Subject, 
                             CreatedBy, 
                             ToReceipientID, 
                             Status,
                             ROW_NUMBER() OVER(ORDER BY '+ @p_SortExpression +') AS Indexing
                      FROM (SELECT ID,
                                   DateTime, 
                                   Subject, 
                                   CreatedBy, 
                                   ToReceipientID, 
                                   SenderStatus AS Status
                             FROM ComposeMail 
                             WHERE (CreatedBy = @p)
                               AND (SenderStatus = 7 OR SenderStatus = 8)
                             UNION
                             SELECT ID,
                                    DateTime, 
                                    Subject, 
                                    CreatedBy, 
                                    ToReceipientID, 
                                    ReceiverStatus As Status
                              FROM ComposeMail
                              WHERE (ToReceipientID = @p1) 
                                AND (ReceiverStatus = 7 OR ReceiverStatus = 8)) AS NewDataTable
            ) AS IndexTable
   WHERE 
       Indexing > @p2 AND Indexing<= (@p2+@p3)' 

   DECLARE @paramDefinition NVARCHAR(500)

   SET @paramDefinition = N'@p UNIQUEIDENTIFIER ,@p1 UNIQUEIDENTIFIER, @p2 INT, @p3 INT'

   EXEC sp_executesql @sql, @paramDefinition,
                @p = @p_CreatedBy,
                @p1 = @p_ToReceipientID,
                @p2 = @p_StartIndex ,
                @p3 = @p_MaxRows

Answer 1

1）我将您的SQL重新编写为：

WITH trash_list AS (
SELECT cm.id,
       cm.datetime, 
       cm.subject,
       cm.createdby,
       cm.toreceipientid, 
       cm.senderstatus AS Status
  FROM COMPOSEMAIL cm
 WHERE cm.createdBy = @p
   AND cm.enderStatus IN(7, 8)
UNION
SELECT cm.id,
       cm.datetime, 
       cm.subject,
       cm.createdby,
       cm.toreceipientid, 
       cm.receiverstatus AS Status
  FROM COMPOSEMAIL cm
 WHERE cm.toreceipientid = @p1
   AND cm.receiverstatus IN (7, 8))
SELECT t.id,
       t.datetime, 
       t.subject,
       t.createdby,
       t.toreceipientid, 
       t.status
  FROM (SELECT tl.id,
               tl.datetime, 
               tl.subject,
               tl.createdby,
               tl.toreceipientid, 
               tl.status,
               ROW_NUMBER() OVER(ORDER BY '+ @p_SortExpression +') AS Indexing
          FROM trash_list tl
      GROUP BY tl.id,
               tl.datetime, 
               tl.subject,
               tl.createdby,
               tl.toreceipientid, 
               tl.status) t
 WHERE t.indexing BETWEEN @p2 AND (@p2+@p3)

...但是，如果仍然有重复项，请检查WITH子句中SELECT / UNION中的逻辑。

在将其转换为动态SQL之前，使其能够像普通SQL一样工作。

2）该查询对于注入攻击是不安全的，因为当用户可以提供文本时，您不会处理单引号：

IF LEN(@p_SortExpression)=0 
  SET @p_SortExpression ='DateTime DESC'

...应该：

IF LEN(@p_SortExpression)=0 
  SET @p_SortExpression ='DateTime DESC'
ELSE
  SET @p_SortExpression = REPLACE(@p_SortExpression, '''', '''''')

Answer 2

您不需要查询和联合。 代替这2行（每个子查询一个）

                         WHERE (CreatedBy = @p)
                         WHERE (ToReceipientID = @p1) 

做到这一点（在一个查询中）

                         WHERE CreatedBy IN (@p, @p1)

像这样：

SELECT
      ID
    , DateTime
    , Subject
    , CreatedBy
    , ToReceipientID
    , Status
FROM (
      SELECT
            ID
          , DateTime
          , Subject
          , CreatedBy
          , ToReceipientID
          , SenderStatus AS Status
          , ROW_NUMBER() OVER (ORDER BY ' + @p_SortExpression + ') AS Indexing
      FROM ComposeMail
      WHERE CreatedBy IN (@p, @p1)
            AND (SenderStatus = 7
            OR SenderStatus = 8)
) AS IndexTable
WHERE Indexing > @p2
      AND Indexing <= (@p2 + @p3)

但是我不确定我是否理解您如何传递@p或@ p1的值