Where子句中的SQL Row_Number（）函数

我Row_Number()在where子句中找到了一个用函数回答的问题。当我尝试一个查询时，出现以下错误：

“消息4108，级别15，状态1，第1行窗口函数只能出现在SELECT或ORDER BY子句中。”

这是我尝试过的查询。如果有人知道如何解决此问题，请告诉我。

SELECT employee_id 
FROM V_EMPLOYEE 
WHERE row_number() OVER ( ORDER BY employee_id ) > 0 
ORDER BY Employee_ID

要解决此问题，请将您的select语句包装在CTE中，然后可以查询CTE并在where子句中使用窗口函数的结果。

WITH MyCte AS 
(
    select   employee_id,
             RowNum = row_number() OVER ( order by employee_id )
    from     V_EMPLOYEE 
    ORDER BY Employee_ID
)
SELECT  employee_id
FROM    MyCte
WHERE   RowNum > 0

SELECT  employee_id
FROM    (
        SELECT  employee_id, ROW_NUMBER() OVER (ORDER BY employee_id) AS rn
        FROM    V_EMPLOYEE
        ) q
WHERE   rn > 0
ORDER BY
        Employee_ID

请注意，此过滤器是多余的：ROW_NUMBER()从开始1并始终大于0。

Select * from 
(
    Select ROW_NUMBER() OVER ( order by Id) as 'Row_Number', * 
    from tbl_Contact_Us
) as tbl
Where tbl.Row_Number = 5

我想你想要这样的东西：

SELECT employee_id 
FROM  (SELECT employee_id, row_number() 
       OVER (order by employee_id) AS 'rownumber' 
       FROM V_EMPLOYEE) TableExpressionsMustHaveAnAliasForDumbReasons
WHERE rownumber > 0

为了回应关于rexem答案的评论，关于内联视图或CTE是否更快，我重新编写了查询以使用表I，并且每个人都可以使用：sys.objects。

WITH object_rows AS (
    SELECT object_id, 
        ROW_NUMBER() OVER ( ORDER BY object_id) RN
    FROM sys.objects)
SELECT object_id
FROM object_rows
WHERE RN > 1

SELECT object_id
FROM (SELECT object_id, 
        ROW_NUMBER() OVER ( ORDER BY object_id) RN
    FROM sys.objects) T
WHERE RN > 1

生成的查询计划完全相同。我希望在所有情况下，查询优化器都会提出相同的计划，至少是用内联视图简单地替换CTE，反之亦然。

当然，请在您自己的系统上尝试自己的查询以查看是否存在差异。

另外，row_number()在where子句中，Stack Overflow给出的答案是一个常见错误。row_number()在处理select子句之前，逻辑上不可用。人们会忘记这一点，当他们在不测试答案的情况下回答问题时，答案有时是错误的。（我本人已犯有罪。）

我觉得所有显示使用CTE或子查询的答案都足以解决此问题，但我看不出有人对OP为何会出现问题深感兴趣。OP建议不起作用的原因是由于此处的逻辑查询处理顺序：

1. 从
2. 上
3. 加入
4. 哪里
5. 通过...分组
6. 与多维数据集/汇总
7. 拥有
8. 选择
9. 不同
10. 订购
11. 最佳
12. 偏移/ FETCH

我相信这对答案很有帮助，因为它解释了为什么会发生此类问题。WHERE在SELECT对许多功能进行必要的CTE或子查询之前，始终会处理。您将在SQL Server中看到很多。

使用CTE（SQL Server 2005+）：

WITH employee_rows AS (
  SELECT t.employee_id,
         ROW_NUMBER() OVER ( ORDER BY t.employee_id ) 'rownum'
    FROM V_EMPLOYEE t)
SELECT er.employee_id
  FROM employee_rows er
 WHERE er.rownum > 1

使用内联视图/非CTE等效替代方法：

SELECT er.employee_id
  FROM (SELECT t.employee_id,
               ROW_NUMBER() OVER ( ORDER BY t.employee_id ) 'rownum'
          FROM V_EMPLOYEE t) er
 WHERE er.rownum > 1

根据OP对问题的回答：

请查看此链接。它有不同的解决方案，对于提出该问题的人来说似乎很有用。我正在尝试找出这样的解决方案。

在SQL Server 2005中使用ROW_NUMBER（）OVER（）对不同的列进行排序的分页查询

约瑟夫

“方法1”就像来自链接问题的OP查询，而“方法2”就像来自所选答案的查询。您必须查看此答案中链接的代码以查看实际情况，因为修改了所选答案中的代码以使其起作用。试试这个：

DECLARE @YourTable table (RowID int not null primary key identity, Value1 int, Value2 int, value3 int)
SET NOCOUNT ON
INSERT INTO @YourTable VALUES (1,1,1)
INSERT INTO @YourTable VALUES (1,1,2)
INSERT INTO @YourTable VALUES (1,1,3)
INSERT INTO @YourTable VALUES (1,2,1)
INSERT INTO @YourTable VALUES (1,2,2)
INSERT INTO @YourTable VALUES (1,2,3)
INSERT INTO @YourTable VALUES (1,3,1)
INSERT INTO @YourTable VALUES (1,3,2)
INSERT INTO @YourTable VALUES (1,3,3)
INSERT INTO @YourTable VALUES (2,1,1)
INSERT INTO @YourTable VALUES (2,1,2)
INSERT INTO @YourTable VALUES (2,1,3)
INSERT INTO @YourTable VALUES (2,2,1)
INSERT INTO @YourTable VALUES (2,2,2)
INSERT INTO @YourTable VALUES (2,2,3)
INSERT INTO @YourTable VALUES (2,3,1)
INSERT INTO @YourTable VALUES (2,3,2)
INSERT INTO @YourTable VALUES (2,3,3)
INSERT INTO @YourTable VALUES (3,1,1)
INSERT INTO @YourTable VALUES (3,1,2)
INSERT INTO @YourTable VALUES (3,1,3)
INSERT INTO @YourTable VALUES (3,2,1)
INSERT INTO @YourTable VALUES (3,2,2)
INSERT INTO @YourTable VALUES (3,2,3)
INSERT INTO @YourTable VALUES (3,3,1)
INSERT INTO @YourTable VALUES (3,3,2)
INSERT INTO @YourTable VALUES (3,3,3)
SET NOCOUNT OFF

DECLARE @PageNumber     int
DECLARE @PageSize       int
DECLARE @SortBy         int

SET @PageNumber=3
SET @PageSize=5
SET @SortBy=1


--SELECT * FROM @YourTable

--Method 1
;WITH PaginatedYourTable AS (
SELECT
    RowID,Value1,Value2,Value3
        ,CASE @SortBy
             WHEN  1 THEN ROW_NUMBER() OVER (ORDER BY Value1 ASC)
             WHEN  2 THEN ROW_NUMBER() OVER (ORDER BY Value2 ASC)
             WHEN  3 THEN ROW_NUMBER() OVER (ORDER BY Value3 ASC)
             WHEN -1 THEN ROW_NUMBER() OVER (ORDER BY Value1 DESC)
             WHEN -2 THEN ROW_NUMBER() OVER (ORDER BY Value2 DESC)
             WHEN -3 THEN ROW_NUMBER() OVER (ORDER BY Value3 DESC)
         END AS RowNumber
    FROM @YourTable
    --WHERE
)
SELECT
    RowID,Value1,Value2,Value3,RowNumber
        ,@PageNumber AS PageNumber, @PageSize AS PageSize, @SortBy AS SortBy
    FROM PaginatedYourTable
    WHERE RowNumber>=(@PageNumber-1)*@PageSize AND RowNumber<=(@PageNumber*@PageSize)-1
    ORDER BY RowNumber



--------------------------------------------
--Method 2
;WITH PaginatedYourTable AS (
SELECT
    RowID,Value1,Value2,Value3
        ,ROW_NUMBER() OVER
         (
             ORDER BY
                 CASE @SortBy
                     WHEN  1 THEN Value1
                     WHEN  2 THEN Value2
                     WHEN  3 THEN Value3
                 END ASC
                ,CASE @SortBy
                     WHEN -1 THEN Value1
                     WHEN -2 THEN Value2
                     WHEN -3 THEN Value3
                 END DESC
         ) RowNumber
    FROM @YourTable
    --WHERE  more conditions here
)
SELECT
    RowID,Value1,Value2,Value3,RowNumber
        ,@PageNumber AS PageNumber, @PageSize AS PageSize, @SortBy AS SortBy
    FROM PaginatedYourTable
    WHERE 
        RowNumber>=(@PageNumber-1)*@PageSize AND RowNumber<=(@PageNumber*@PageSize)-1
        --AND more conditions here
    ORDER BY
        CASE @SortBy
            WHEN  1 THEN Value1
            WHEN  2 THEN Value2
            WHEN  3 THEN Value3
        END ASC
       ,CASE @SortBy
            WHEN -1 THEN Value1
            WHEN -2 THEN Value2
            WHEN -3 THEN Value3
        END DESC

输出：

RowID  Value1 Value2 Value3 RowNumber  PageNumber  PageSize    SortBy
------ ------ ------ ------ ---------- ----------- ----------- -----------
10     2      1      1      10         3           5           1
11     2      1      2      11         3           5           1
12     2      1      3      12         3           5           1
13     2      2      1      13         3           5           1
14     2      2      2      14         3           5           1

(5 row(s) affected

RowID  Value1 Value2 Value3 RowNumber  PageNumber  PageSize    SortBy
------ ------ ------ ------ ---------- ----------- ----------- -----------
10     2      1      1      10         3           5           1
11     2      1      2      11         3           5           1
12     2      1      3      12         3           5           1
13     2      2      1      13         3           5           1
14     2      2      2      14         3           5           1

(5 row(s) affected)

WITH MyCte AS 
(
    select 
       employee_id,
       RowNum = row_number() OVER (order by employee_id)
    from V_EMPLOYEE 
)
SELECT  employee_id
FROM    MyCte
WHERE   RowNum > 0
ORDER BY employee_id

 select salary from (
 select  Salary, ROW_NUMBER() over (order by Salary desc) rn from Employee 
 ) t where t.rn = 2