Change a Nullable column to NOT NULL with Default Value

SqlSql ServerDefault ValueAlter TableAlter Column

Sql Problem Overview


I came across an old table today with a datetime column called 'Created' which allows nulls. Now, I'd want to change this so that it is NOT NULL, and also include a constraint to add in a default value (getdate()).

So far I've got the following script, which works fine provided that i've cleaned up all the nulls beforehand:

ALTER TABLE dbo.MyTable ALTER COLUMN Created DATETIME NOT NULL 

Is there any way to also specify the default value as well on the ALTER statement?

Sql Solutions


Solution 1 - Sql

I think you will need to do this as three separate statements. I've been looking around and everything i've seen seems to suggest you can do it if you are adding a column, but not if you are altering one.

ALTER TABLE dbo.MyTable
ADD CONSTRAINT my_Con DEFAULT GETDATE() for created

UPDATE MyTable SET Created = GetDate() where Created IS NULL

ALTER TABLE dbo.MyTable 
ALTER COLUMN Created DATETIME NOT NULL 

Solution 2 - Sql

You may have to first update all the records that are null to the default value then use the alter table statement.

Update dbo.TableName
Set
Created="01/01/2000"
where Created is NULL

Solution 3 - Sql

you need to execute two queries:

One - to add the default value to the column required

> ALTER TABLE 'Table_Name` ADD DEFAULT 'value' FOR 'Column_Name'

i want add default value to Column IsDeleted as below:

> Example: ALTER TABLE [dbo].[Employees] ADD Default 0 for IsDeleted

Two - to alter the column value nullable to not null

> ALTER TABLE 'table_name' ALTER COLUMN 'column_name' 'data_type' NOT NULL

i want to make the column IsDeleted as not null

> ALTER TABLE [dbo].[Employees] Alter Column IsDeleted BIT NOT NULL

Solution 4 - Sql

If its SQL Server you can do it on the column properties within design view

Try this?:

ALTER TABLE dbo.TableName 
  ADD CONSTRAINT DF_TableName_ColumnName
    DEFAULT '01/01/2000' FOR ColumnName

Solution 5 - Sql

Try this > ALTER TABLE table_name ALTER COLUMN col_name data_type NOT NULL;

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Content TypeOriginal AuthorOriginal Content on Stackoverflow
QuestionJim BView Question on Stackoverflow
Solution 1 - SqlAbe MiesslerView Answer on Stackoverflow
Solution 2 - SqlGageView Answer on Stackoverflow
Solution 3 - SqlJinna BaluView Answer on Stackoverflow
Solution 4 - SqlBenWView Answer on Stackoverflow
Solution 5 - Sqlbelal ahmadView Answer on Stackoverflow