Interested to Buy Any Domain ? << Click Here >> for more details...
Can we have more than one NULL in a column having unique
constraint?
- 12 Answers
- 16940 Views
- 247Customer, I also Faced
- E-Mail Answers
Answers were Sorted based on User's Feedback
Answer / kalu
No, because Unique constraint accepts only one null value.
| Is This Answer Correct ? | 16 Yes | 3 No |
Answer / p.prabhu
No we cant have More than One Null in a column which is
having Unique Key Constraint. Because Unique Key Constraint
means having a value only once in the column.
| Is This Answer Correct ? | 4 Yes | 1 No |
Answer / santhoshkumar.k
No we can not have that option in sql server
| Is This Answer Correct ? | 4 Yes | 2 No |
Answer / krishnaraj p n
UNIQUE constraints can accept NULL just once. If the
constraint is defined in a combination of fields, then
every field can accept NULL and can have some values on
them, as long as the combination values is unique.
| Is This Answer Correct ? | 2 Yes | 0 No |
No this is not possible... columns with Unique constraint
can only contain 1 null value/row.
@Manish... could you please try this:
create table #tempTable (id int, name varchar(50) unique)
insert into #tempTable
select 1, 'manoj' union
select 2, null union
select 3, null union
select 4, 'pandey'
| Is This Answer Correct ? | 1 Yes | 0 No |
Answer / maneesh
Yes there can be any number of NULLs.
Remember NULL <> NULL.
So uniqueness will still be there.
Just try it out.
Maneesh
| Is This Answer Correct ? | 6 Yes | 6 No |
Answer / habibur rahaman
It depends upon the database on which you are working.....in SQL we can have only one value but in oracle we can have n no of values.......i did it practically.
| Is This Answer Correct ? | 0 Yes | 0 No |
Answer / sasikumar
It is possible in Oracle database (NULL <> NULL) but not
possible in SQL server.
| Is This Answer Correct ? | 1 Yes | 1 No |
Answer / drona
UNIQUE constraints can accept NULL just once.
I have a dought?
Every null is different?
| Is This Answer Correct ? | 0 Yes | 0 No |
What is the difference between HAVING clause and the WHERE clause?
What is the stuff?
Mention the differences between sql server and mysql.
What xml support does the sql server extend?
What is the difference between windows authentication and sql server authentication
what is the difference in login security modes between v6.5 and 7.0? : Sql server database administration
What are the type of joins? When do we use Outer and Self joins?
Why does sql studio use a single registered database repository? : sql server management studio
how many non clustered index in sql server 2008,2010,2012
Can we use having clause without group by?
Hi Can any one tell me the Good institute to learn SQL esp for Data Base Testing or SQL from scratch to the proficiency level in Hyederabad and facult also. Thankyou well in advance
How to check if a table is being used in sql server?
-
Oracle (3253) - SQL Server (4518)
- MS Access (429)
- MySQL (1402)
- Postgre (483)
- Sybase (267)
- DB Architecture (141)
- DB Administration (291)
- DB Development (113)
- SQL PLSQL (3330)
- MongoDB (502)
- IBM Informix (50)
- Neo4j (82)
- InfluxDB (0)
- Apache CouchDB (44)
- Firebird (5)
- Database Management (1411)
- Databases AllOther (288)
