Printing only distinct rows from a sql Table

Question

This was asked to me interview and i am beginner in sql so was unable to solve it.
we are given a table in which somehow some of the rows are duplicated but now we only want distinct rows

Name id orderNo
----------------
Mark 1 order1
Mark 1 order2
Mark 1 order2
Allen 3 order 2
Allen 3 order 3
Allen 3 order 3
Dennis 5 order 7
Dennis 5 order 9

Result

Mark 1 order1
Mark 1 order2
Allen 3 order 2
Allen 3 order 3
Dennis 5 order 7
Dennis 5 order 9

I answered

SELECT DISTINCT * from TableName;

but he wanted some other approach

As the [guidelines](https://stackoverflow.com/help/how-to-ask) suggest, you naturally researched before posting a question here... What did you find, and why didn't it answer your question? — HoneyBadger, Aug 27 '22 at 11:17
"he wanted some other approach". I think you should have started asking why another approach than this would be needed. The only thing worth changing is change `*` to the list of field names. — Luuk, Aug 27 '22 at 12:09
in interview after wondering for a while i asked for hint he said you can use group by — Aditya Patel, Aug 30 '22 at 10:52

score 2 · Answer 1 · answered Aug 27 '22 at 11:08

2

DISTINCT keyword used to select unique records. Following query will help you.

SELECT DISTINCT Name, Id, OrderNo from TableName

answered Aug 27 '22 at 11:08

Abhijeet Khandagale

89
6

score 1 · Accepted Answer · answered Aug 27 '22 at 12:05

1

You could also use Group by clause to achieve this. Group the record by all of these column.

SELECT Name,id,orderNo
    FROM TableName
    GROUP BY Name,id,orderNo

answered Aug 27 '22 at 12:05

Alpha

1,413
3
9
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score -1 · Answer 3 · answered Aug 27 '22 at 12:11

-1

SELECT DISTINCT * FROM TableName;

The above query would work.

answered Aug 27 '22 at 12:11

Karthik Bhandary

1,305
2
7
16

Printing only distinct rows from a sql Table

3 Answers3