Question

我有以下格式的存储过程

SELECT key1 AS FirstKey, key2 AS SecondKey FROM table
ORDER BY
    CASE @sortOrderParam WHEN 'ASC' THEN
        CASE UPPER(@sortColumn)
        WHEN 'blabla' THEN FirstKey
        WHEN 'blibli' THEN FirstKey, SecondKey --Syntax error
        END
    END ASC,
    CASE @sortOrderParam WHEN 'DESC' THEN
    ...
    END DESC

但是，在某些情况下尝试按两列排序时出现语法错误。我怎么能这样做？

谢谢！

Answer 1

Case只能返回一个特定值，而不是一组列。你需要以不同的方式分解它，或许像：

SELECT key1 AS FirstKey, key2 AS SecondKey FROM table
ORDER BY
FirstKey, 
CASE @sortOrderParam WHEN 'ASC' THEN
    CASE UPPER(@sortColumn)
    WHEN 'blibli' THEN SecondKey --only relevant when blibli
    END
END ASC,
CASE @sortOrderParam WHEN 'DESC' THEN
...
END DESC

您还可以通过附加适当的数据来构建排序列。

订购多个密钥和案例

1 个答案: