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Can we have more than one NULL in a column having unique
constraint?
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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 |
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