sql server How to skip rows with same column values in SQL Server? group and repeat

.sql

--https://stackoverflow.com/questions/55249646/how-to-skip-rows-with-same-column-values-in-sql-server

CREATE TABLE T(
  Col1 INT,
  Col2 VARCHAR(45),
  Col3 VARCHAR(45)
);

INSERT INTO T VALUES
(1, 'Steve',  'Rodgers'),  
(2, 'Tony',  'Stark' ), 
(3, 'Steve',  'Jobs');

SELECT *
FROM T
WHERE 1 = (SELECT COUNT(Col2) 
           FROM T TT 
           
           --------------------------------
           
           select * from tablename t
where not exists (
  select 1 from tablename
  where colb = t.colb and cola <> t.cola
)


--------------------------------


select min(cola) as col1, colb, min(colc) as colc
from t
group by colb
having count(*) = 1;
           WHERE T.Col2 = TT.Col2 
          );