我如何查询表以在MS Access中查找重复的备忘录字段?
还请注意,我的表中没有主键。
这是一种可能的方法:
select t.MemoField
from YourTable t
group by t.MemoField
having count(*) > 1
要测试跨多个字段重复,您可以使用:
select t.MemoField1, t.MemoField2, t.MemoField3
from YourTable t
group by t.MemoField, t.MemoField2, t.MemoField3
having count(*) > 1
如果 Name
是主要键列,而 MemoColumn
是要查找重复项的列,则可以使用 EXISTS
:
SELECT t.* FROM tablename AS t
WHERE EXISTS (
SELECT 1 FROM tablename AS tt
WHERE t.Name <> tt.Name and t.MemoColumn = tt.MemoColumn
)