Question

我有一个数据集查询如下：

SELECT col1, col2
FROM Table
WHERE @DatabaseGrowth = 'DatabaseGrowthByLast7Days'

UNION ALL

SELECT col3, col4
FROM Table
WHERE @DatabaseGrowth = 'DatabaseGrowthByLast4Weeks'

并有一个名为DatabaseGrowth的参数。运行报告时，如果我选择DatabaseGrowthByLast7Days，则应返回7Days。但是，它显示错误

必须声明标量变量“@DatabaseGrowth”

我的数据集代码有什么问题？上面的代码是我实际代码的示例代码。

编辑上面的代码。

Answer 1

尝试以下方式，如果您在SSRS数据集中使用它，则无需声明它。如果删除现有参数并将以下代码添加到数据集。它会自动创建一个名为DatabaseGrowth的参数。

SELECT col1, col2
FROM Table
WHERE 'DatabaseGrowthByLast7Days' = (@DatabaseGrowth)

UNION ALL

SELECT col3, col4
FROM Table
WHERE 'DatabaseGrowthByLast4Weeks' = (@DatabaseGrowth)

Answer 2

declare @DatabaseGrowth varchar(500)= 'DatabaseGrowthByLast4Weeks'
SELECT '7Days' as val
WHERE @DatabaseGrowth = 'DatabaseGrowthByLast7Days'

UNION ALL

SELECT '4Weeks' as val
WHERE @DatabaseGrowth = 'DatabaseGrowthByLast4Weeks'

Answer 3

首先，您需要声明变量@DatabaseGrowth。然后你可以使用CASE表达式：

评估条件列表并返回多个可能的结果表达式之一。

DECLARE @DatabaseGrowth nvarchar(max) = 'DatabaseGrowthByLast7Days'

SELECT CASE WHEN @DatabaseGrowth = 'DatabaseGrowthByLast4Weeks' THEN '4Weeks' 
            WHEN @DatabaseGrowth = 'DatabaseGrowthByLast7Days' THEN '7Days'  
            ELSE NULL END as val

或者：

SELECT CASE @DatabaseGrowth  
            WHEN 'DatabaseGrowthByLast4Weeks' THEN '4Weeks' 
            WHEN 'DatabaseGrowthByLast7Days' THEN '7Days'  
            ELSE NULL END as val

修改

根据您的修改：

DECLARE @DatabaseGrowth nvarchar(max) = 'DatabaseGrowthByLast4Weeks' SELECT [Col1], [Col2] FROM [Table] WHERE @DatabaseGrowth = 'DatabaseGrowthByLast7Days' UNION ALL SELECT [Col3], [Col4] FROM [Table] WHERE @DatabaseGrowth = 'DatabaseGrowthByLast4Weeks'

请注意，[Col1]应与[Col3]的数据类型相同，[Col2]与[Col4]的数据类型相同。

必须声明Scalar变量 - 参数中的错误

3 个答案: