Differences between UNIQUE and DISTINCT in select statements

Categories >> Software >> Databases >> SQL PLSQL
Suggest New Category

Question Posted / cutepa1

26 Answers
130854 Views
ABS, DELL, Deloitte, Hewitt, Oracle, Verinon Technology Solutions, Wipro, I also Faced
E-Mail Answers

Answers were Sorted based on User's Feedback

Differences between UNIQUE and DISTINCT in select statements..

Answer / kkparambath

SELECT DISTINCT Example

The "Persons" table:
P_Id LastName FirstName Address City
1 Hansen Ola Timoteivn10 Sandnes
2 Svendson Tove Borgvn 23 Sandnes
3 Pettersen Kari Storgt 20 Stavanger

Now we want to select only the distinct values from the
column named "City" from the table above.

We use the following SELECT statement:
SELECT DISTINCT City FROM Persons

The result-set will look like this:
City
Sandnes
Stavanger

Is This Answer Correct ?

7 Yes

9 No

Differences between UNIQUE and DISTINCT in select statements..

Answer / chandrakant agrawal

Let us try one using :

select distinct dept_name
from departments;

What this query would return if dept_name column contains
NULL values.

Is This Answer Correct ?

3 Yes

11 No

Differences between UNIQUE and DISTINCT in select statements..

Answer / satish parashar

After applying the unique clause all the value of column
will be sorted, But in distinct clause it only remove the
duplicacy from the table,not sorted the column value.

Is This Answer Correct ?

6 Yes

15 No

Differences between UNIQUE and DISTINCT in select statements..

Answer / apparao akki

Hi all,

plz find the below executed report on the same.
------------------------------------------------------

SQL> select * from person;

PERSON_ID FIRST_NAME LAST_NAME
TITLE_1 TITLE_2 SOCS
---------- --------------------- -------------------------
---------- ---------- -----------
9 ssss rrrrr
tttt gggg 67778-3
1 THUUTHTUT lofstrom
ba null 4940-343
1 ffsdf fsdfsd
fdsfsd fsdf 5454
1 THUUTHTUT lofstrom
ba null 4940-343
1 THUUTHTUT lofstrom
ba null 4940-343
1 appa akki
s/w btech 3i
2 rao
s/w kmm 3i
4 bunny neel
lkg ukg home

8 rows selected.

SQL> select unique(person_id),last_name from person;

PERSON_ID LAST_NAME
---------- -------------------------
2
1 lofstrom
4 neel
1 fsdfsd
9 rrrrr
1 akki

6 rows selected.

SQL> select distinct(person_id) from person;

PERSON_ID
----------
4
9
2
1

Is This Answer Correct ?

9 Yes

20 No

Differences between UNIQUE and DISTINCT in select statements..

Answer / vidya

unique allows null value but distinct does not consider
null value

Is This Answer Correct ?

2 Yes

44 No

Differences between UNIQUE and DISTINCT in select statements..

Answer / guest

UNIQUE and DISTINCT

Is This Answer Correct ?

32 Yes

100 No

Post New Answer