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我有下面的SQL查詢,我很確定我正在接近它不正確。我想回到那個不具有的值爲「王」Microsoft Access爲空問題
SELECT DISTINCT o.Object_ID, o.ea_guid as CLASSGUID, o.Object_Type as CLASSTYPE, o.name as Name, type.value as RoomType
FROM ((t_object as o
INNER JOIN t_objectproperties as location
ON o.Object_ID = location.Object_ID)
INNER JOIN t_objectproperties as type
ON o.Object_ID = type.Object_ID)
WHERE location.Property = 'Location'
AND location.Value = 'Queens'
AND type.Property = 'King' IS NULL
謝謝。我在發佈問題後意識到了這一點。我遇到的問題是當我使用'iif'函數即IIF(type.Property <>'RoomType',「None」,「Yes」)時。它返回所有屬性,包括RoomType – PeanutsMonkey
不能爲null,IIF(type.Property <>'RoomType',「None」,「Yes」)<>'None',也許。順便提一下你的問題,而不是完全不同的問題 –