SQL Server 2022

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CREATE TABLE mytable(
   row_id INTEGER  NOT NULL 
  ,id     int  NOT NULL
  ,col_a  VARCHAR(30) NOT NULL
  ,col_b  VARCHAR(30) NOT NULL
);
INSERT INTO mytable
(row_id,id,col_a,col_b) VALUES 
(1,1,'value_a','value_b'),
(2,1,'value_a','value_c'),
(3,1,'value_d','value_c'),
(4,1,'value_e','value_c'),
(5,1,'value_f','value_g'),
(7,1,'value_d','value_c');/*Repeated value*/
--(7,1,'value_b','value_c'); /*that is not a Repeated value, it is whole new value*/
6 rows affected

WITH t
     AS (SELECT *,
                DENSE_RANK()
                  OVER(
                    partition BY id, col_b
                    ORDER BY col_a ) id2
         FROM   mytable)


SELECT min(row_id) row_id ,id,col_a,col_b
FROM   t
WHERE  id2 > 1  
group by id,col_a,col_b


row_id
id
col_a
col_b


3
1
value_d
value_c

4
1
value_e
value_c


WITH t
     AS (SELECT *,
                Dense_rank()
                  OVER(
                    partition BY id, col_b
                    ORDER BY col_a ) id2
         FROM   mytable),
/*new CTE*/
     a
     AS (SELECT row_id,
                id,
                col_a,
                col_b,
                Row_number()
                  OVER(
                    partition BY id, col_a, col_b
                    ORDER BY row_id ) id3
         FROM   t
         WHERE  id2 > 1)
SELECT row_id,
       id,
       col_a,
       col_b
FROM   a
WHERE  id3 = 1  


row_id
id
col_a
col_b


3
1
value_d
value_c

4
1
value_e
value_c