I have these Attributes in a table ABC 

Location, Zone, Sector, UnitNo

and want to write a query for them where Location and UnitNo are same but Sector is different
means I have sectors in different locations where UnitNo is same

I wrote this one but does not work.

```
select * from ABC A1 Inner JOIN ABC A2 on A1.Id = A2.ID
WHERE 
A1.Sector <> A2.Sector AND A1.Location = A2.Location ANd A1.UnitNo = A2.UnitNo

```

please help.