database - Distinct or Union is selecting duplicate data in SQL Server

Question

I have a table with 526 rows and has lot of duplicate data. For removing duplicate I used this script:

select distinct fullname, RegistrationNumber
from tbllookupStudentInfo1;

I got 291 rows, but it still has duplicate column so I tried using union:

select distinct fullname, RegistrationNumber
from tbllookupStudentInfo1
union 
select fullname,RegistrationNumber
from tbllookupStudentInfo1;

I got 291 rows, but still I am getting few duplicate value. And then I select just Fullname using both union and distinct and got 213 rows which consists few duplicate fullname too. How should I solve this?

question from:https://stackoverflow.com/questions/65643343/distinct-or-union-is-selecting-duplicate-data-in-sql-server

Answer 1

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