Question

我使用的是SQL Server 2008，我希望根据输入列名和排序顺序（asc / desc）对数据进行排序。如何使下面的查询动态化？

DECLARE @iColumnName VARCHAR(24);
DECLARE @iSortOrder VARCHAR(10);

SET @iColumnName = 'ReceiptLocation'; -- ReceiptLocation/DeliverLocation/NominationNbr
SET @iSortOrder = 'DESC'; -- DESC / ASC

SELECT sum(NominationNbr)
    ,sum(ReceiptLocation)
    ,sum(DeliverLocation)
FROM tables
GROUP BY NominationNbr
    ,ReceiptLocation
    ,DeliverLocation
ORDER BY CASE @iColumnName
        WHEN 'ReceiptLocation'
            THEN ReceiptLocation
        WHEN 'DeliverLocation'
            THEN DeliverLocation
        ELSE NominationNbr
        END   

        CASE @iSortOrder
        WHEN 'DESC'
            THEN DESC
        ELSE ASC
        END

Answer 1

你需要将两者结合起来。我会建议这个相当笨重的代码：

ORDER BY (CASE WHEN @iColumnName = 'ReceiptLocation' AND @iSortOrder = 'DESC'
               THEN ReceiptLocation
          END) DESC,
         (CASE WHEN @iColumnName = 'ReceiptLocation' 
               THEN ReceiptLocation
          END) ASC,
         (CASE WHEN @iColumnName = 'DeliverLocation' AND @iSortOrder = 'DESC'
               THEN DeliverLocation
          END) DESC,
         (CASE WHEN @iColumnName = 'DeliverLocation' 
               THEN DeliverLocation
          END) ASC,
         (CASE WHEN @iSortOrder = 'DESC'
               THEN NominationNbr
          END) DESC,
         NominationNbr ASC

每个CASE语句都是一个单独的订单键。但是，如果它们不匹配，则值为NULL，因此密钥不会执行任何不匹配的操作。

您也可以使用动态SQL实现此功能。如果您有一个简单的查询和可用于ORDER BY的索引，那么这可能会更有效。

如何使order by子句动态化

1 个答案: