SQL Find first occurrence of row in table

Question

id name marks 
1;"mohit";10
2;"mohit";20
3;"raj";30
4;"rupesh";40
5;"rupesh";50

Expected output is :

1;"mohit";10
4;"rupesh";40

Answer 1

Try this

SELECT * 
FROM Your_Table
WHERE ID IN (
             SELECT Min(ID)
             FROM Your_Table
             GROUP BY Name
             HAVING Count(*) > 1
)

Answer 2

I think DISTINCT ON should work here:

SELECT DISTINCT ON (name) name, id, marks
FROM your_table
ORDER BY name, id;

This assumes that you want the first row of each person with regard to the id .

Demo

Late Edit:

It looks like you want the first record from each name group where a name appears at least two or more times. We can try the following query:

SELECT id, name, marks
FROM
(
    SELECT *,
        ROW_NUMBER() OVER (PARTITION BY name ORDER BY id) rn,
        COUNT(*) OVER (PARTITION BY name) cnt
    FROM your_table
) t
WHERE rn = 1 AND cnt > 1;

Answer 3

USE GROUP BY TO COUNT MULTIPLE OCCURENCE..

SELECT * FROM table WHERE name IN( SELECT name FROM table GROUP BY name HAVING COUNT(name) > 1)

Answer 4

I think this should work

select * from 
(select ROW_NUMBER() OVER(
    PARTITION BY name
    ORDER BY id ) as rnum , name ,id ,marks
from  your_table) A
where rnum = 1