Question

我有一个存储过程，可以接受2个不同的参数。第一个参数将确定我要排序的列，第二个参数将确定它是ASC还是DESC

Create Procedure Some_SP
    @sortcolumn varchar(10)
    @sortorder varchar(10)
AS
    Select * from empTable
    Order by
         CASE @sortcolumn WHEN 'First_Name' THEN fname END,
         CASE @sortcolumn WHEN 'Last_Name' THEN lname END,
         CASE @sortcolumn WHEN 'ID' THEN empID END,
         CASE @sortorder WHEN 'ascending' THEN ASC END,
         CASE @sortorder WHEN 'descending' THEN DESC END

它给了我语法错误。如何修复它以便我的CASE语句中有两个条件？

Answer 1

以下内容可行：

Select * from empTable
Order by
CASE WHEN @sortcolumn = 'First_Name' AND @SortOrder = 'ascending' THEN fname END ASC,
CASE WHEN @sortcolumn = 'First_Name' AND @SortOrder = 'descending' THEN fname END DESC

等...

为了避免手动输入每个case语句，你可以写一个＆＃34; generator＆＃34;用于创建此脚本的脚本（如果表定义发生更改，则特别好）：

SELECT 
    'CASE WHEN @SortColumn = ''' + C.name + ''' AND @SortOrder = ''ascending'' THEN ' + C.name + ' END ASC,' + CHAR(13) + CHAR(10) +
    'CASE WHEN @SortColumn = ''' + C.name + ''' AND @SortOrder = ''descending'' THEN ' + C.name + ' END DESC,'
FROM sys.columns C 
WHERE C.object_id = object_id('[Schema].[Table]')

Answer 2

如果您想避免动态SQL并使用2x条件，可以使用row_number

例如：

declare @t table (string varchar(50), number int)

insert @t values ('a',9),('f',2),('c',1)

declare 
    @sc varchar(10) = 'number', -- or 'string', etc
    @so varchar(10) = 'desc' -- or 'asc'

select *
from 
(
    select 
        *,
        case @sc when 'string' then ROW_NUMBER() over (order by string)
                 when 'number' then ROW_NUMBER() over (order by number)
        end rn
    from @t
) v
order by 
case @so when 'desc' then -rn else rn end

Answer 3

您只需复制并粘贴并运行即可。我讨厌动态SQL，不要这样做。

不幸的是，您必须复制查询....但它可以解决您的具体问题。

DECLARE
    @sortcolumn varchar(10),
    @sortorder varchar(10)

SET @sortcolumn = 'fname'
SET @sortorder =  'DESC'

DECLARE
    @Data TABLE
        (
        fname nvarchar(10),
        lname nvarchar(10),
        empID int
        )
INSERT INTO @Data VALUES ('BBB', 'BBB', 2)
INSERT INTO @Data VALUES ('AAA', 'AAA', 1)


IF @sortorder = 'DESC' BEGIN

    SELECT
        *
    FROM 
        @Data
    ORDER BY
        CASE 
            WHEN @sortcolumn = 'fname' THEN fname
            WHEN @sortcolumn = 'lname' THEN lname
        END
        DESC

END ELSE BEGIN

    SELECT
        *
    FROM 
        @Data
    ORDER BY
        CASE 
            WHEN @sortcolumn = 'fname' THEN fname
            WHEN @sortcolumn = 'lname' THEN lname
        END

END

Answer 4

修改Jon的答案，将ORDER BY列表限制为2而不是2 * #columns

SELECT *
FROM MyTable
CROSS APPLY (VALUES
  ('First_Name',fname),
  ('Last_Name' ,lname),
  ('Id'        ,ID   )
) sort(SortColumn, SortValue)
WHERE SortColumn = @SortColumn
ORDER BY
  CASE @SortOrder WHEN 'ascending'  THEN SortValue END ASC,
  CASE @SortOrder WHEN 'descending' THEN SortValue END DESC

具有2个条件的SQL案例

4 个答案: