How to find misspellings in data - sql-server

Question

I am trying to find the misspellings in TOWN_C field. Data looks something like below. There is no specific pattern, sometimes misspelling can be at the beginning, sometimes it can be in middle or at the end. Length of misspelling can be different too.
I am using SQL Server Management Studio to execute the queries. I used SUBSTR to find out duplicates along with the left outer join. But that does not give only misspelling. I still need to go and manually look at data.
Data ->
Achampet
ACHEMPET
AGIA
AGIYA
ASHOK NAGAR
ASHOKNAGAR
ASHOKNAGER
SQL query which I am using ->
Select distinct(T3.TOWN__C)
From (Select T1.Sub_Str, Count(T1.Sub_Str) as Y
From (SELECT TOWN__C, SUBSTRING(TOWN__C, 1, 3) as Sub_Str
FROM [SALESFORCE].[dbo].[Outlet Master] group by TOWN__C)T1
Group by T1.Sub_Str having count(*)> 1)T2
Left outer join
[SALESFORCE].[dbo].[Outlet Master]T3
On T2.Sub_Str = SUBSTRING(T3.TOWN__C, 1, 3)
Order by T3.TOWN__C
Is there a way to find out all such cases using SQL or Excel or anything else?

Answer 1

Here's an example using SOUNDEX, to try to locate values where multiple spellings have been used for "similar" names:
declare #t table (town varchar(35) not null)
insert into #t(town) values
('Achampet'),
('ACHEMPET'),
('AGIA'),
('AGIYA'),
('ASHOK NAGAR'),
('ASHOKNAGAR'),
('ASHOKNAGER'),
('Downtown'),
('DOWNTOWN'),
('DownTown')
select
v.*
from
(select
*,
MIN(town) OVER (PARTITION BY town_sound) as minTown,
MAX(town) OVER (PARTITION BY town_sound) as maxTown
from
#t
cross apply
(select SOUNDEX(REPLACE(town,' ','')) as town_sound) u
) v
where minTown != maxTown
Note that this doesn't return "downtown" where the only variations are in capitalization, but does return all of the values in your given sample data, which I assume were all meant to be found as possible misspellings.
Also note that SOUNDEX has had a chequered history and under older versions of SQL Server it was usually recommended that a "better" soundex be implemented as a UDF. You should be able to find versions of that with a simple search, if required.
Note, also, that Soundex was specifically designed around English pronunciation. Again, you may be able to find a better tailored function as a UDF for specific other languages.
Results:
town town_sound minTown maxTown
------------- ---------- ------------- ------------
AGIA A200 AGIA AGIYA
AGIYA A200 AGIA AGIYA
ASHOK NAGAR A225 ASHOK NAGAR ASHOKNAGER
ASHOKNAGAR A225 ASHOK NAGAR ASHOKNAGER
ASHOKNAGER A225 ASHOK NAGAR ASHOKNAGER
Achampet A251 Achampet ACHEMPET
ACHEMPET A251 Achampet ACHEMPET