Question

我有两个表，dimensionStructure和dimensionDetail。当我在Case语句之后加入NOT EXISTS时，一切都很美妙。

SELECT ds.structureName, ds.dimensionName, 'Error' = CASE
when NOT EXISTS (select 1 from dbo.DimensionStructure ds 
                inner join dbo.DimensionDetail dd on dd.dimensionName = ds.dimensionName
                where dd.element!= 'revenue')
    THEN 'You must have at least one dimension that is tied to the element Revenue.'
    ELSE 'Test'
END
from dbo.DimensionStructure ds
where ds.structureType = 'revenue'

但是，如果我尝试在Case语句之外的dimensionDetail中添加一列，突然间我没有得到任何结果。

SELECT ds.structureName, ds.dimensionName, dd.element, 'Error' = CASE
when NOT EXISTS (select 1 from dbo.DimensionStructure ds 
                inner join dbo.DimensionDetail dd on dd.dimensionName = ds.dimensionName
                where dd.element!= 'revenue')
    THEN 'You must have at least one dimension that is tied to the element Revenue.'
    ELSE 'Test'
END
from dbo.DimensionStructure ds
inner join dbo.DimensionDetail dd on dd.dimensionName = ds.dimensionName
where ds.structureType = 'revenue'

我还没有完全理解我做错了什么。

Answer 1

您可以尝试将查询修改为

SELECT ds.structureName, 
ds.dimensionName, 
dd.element, 
CASE
when dd.element != 'revenue'
    THEN 'You must have at least one dimension that is tied to the element Revenue.'
    ELSE 'Test' END AS 'Error'
from dbo.DimensionStructure ds
inner join dbo.DimensionDetail dd on dd.dimensionName = ds.dimensionName
where ds.structureType = 'revenue';

使用内部联接和案例陈述时没有结果

1 个答案: