How to add a column with a default value to an existing table in SQL Server?

Question

How can I add a column with a default value to an existing table in SQL Server 2000 / SQL Server 2005?

Helvetian

Answer 1

Syntax:

ALTER TABLE {TABLENAME} 
ADD {COLUMNNAME} {TYPE} {NULL|NOT NULL} 
CONSTRAINT {CONSTRAINT_NAME} DEFAULT {DEFAULT_VALUE}
WITH VALUES

Example:

ALTER TABLE SomeTable
        ADD SomeCol Bit NULL --Or NOT NULL.
 CONSTRAINT D_SomeTable_SomeCol --When Omitted a Default-Constraint Name is autogenerated.
    DEFAULT (0)--Optional Default-Constraint.
WITH VALUES --Add if Column is Nullable and you want the Default Value for Existing Records.

Notes:

Optional Constraint Name:
If you leave out CONSTRAINT D_SomeTable_SomeCol then SQL Server will autogenerate
    a Default-Contraint with a funny Name like: DF__SomeTa__SomeC__4FB7FEF6

Optional With-Values Statement:
The WITH VALUES is only needed when your Column is Nullable
    and you want the Default Value used for Existing Records.
If your Column is NOT NULL, then it will automatically use the Default Value
    for all Existing Records, whether you specify WITH VALUES or not.

How Inserts work with a Default-Constraint:
If you insert a Record into SomeTable and do not Specify SomeCol's value, then it will Default to 0.
If you insert a Record and Specify SomeCol's value as NULL (and your column allows nulls),
    then the Default-Constraint will not be used and NULL will be inserted as the Value.

Notes were based on everyone's great feedback below.
Special Thanks to:
    @Yatrix, @WalterStabosz, @YahooSerious, and @StackMan for their Comments.

Syl

Keep in mind that if the column is nullable, then null will be the value used for existing rows. – Waterscape

@Thecrocodilehunter Nullable column means that you can insert Null for the columns value. If it's not a nullable column, you have to insert some value of that data type. So, for existing records, Null will be inserted in them and in new records, your default value will be inserted unless otherwise specified. Make sense? – Radtke

I like this answer a little better than dbugger's because it explicitly names the default constraint. A default constraint is still created using dbugger's syntax, except its name is auto-generated. Knowing the exact name is handy when writing DROP-CREATE scripts. – Emmieemmit

Use WITH VALUES to update existing nullable rows. See MSDN: "If the added column allows null values and WITH VALUES is specified, the default value is stored in the new column, added to existing rows." – Topple

When it back-fills the default value, will it fire update triggers and/or take table locks? If so, can they be avoided? – Cheder

Answer 2

ALTER TABLE Protocols
ADD ProtocolTypeID int NOT NULL DEFAULT(1)
GO

The inclusion of the DEFAULT fills the column in existing rows with the default value, so the NOT NULL constraint is not violated.

Vinic

Just to clarify - if "NOT NULL" is omitted from the command, the value for existing rows will NOT be updated and will remain NULL. If "NOT NULL" is included in the command, the value for existing rows WILL be updated to match the default. – Lizalizabeth

For more detailed content; #2524176 – Crescantia

Answer 3

When adding a nullable column, WITH VALUES will ensure that the specific DEFAULT value is applied to existing rows:

ALTER TABLE table_name
ADD column_name BIT     -- Demonstration with NULL-able column added
CONSTRAINT Constraint_name DEFAULT 0 WITH VALUES

Cantu

Answer 4

ALTER TABLE <table name> 
ADD <new column name> <data type> NOT NULL
GO
ALTER TABLE <table name> 
ADD CONSTRAINT <constraint name> DEFAULT <default value> FOR <new column name>
GO

Gimp

Answer 5

ALTER TABLE MYTABLE ADD MYNEWCOLUMN VARCHAR(200) DEFAULT 'SNUGGLES'

Burkle

Answer 6

The most basic version with two lines only

ALTER TABLE MyTable
ADD MyNewColumn INT NOT NULL DEFAULT 0

Laktasic

Answer 7

Beware when the column you are adding has a NOT NULL constraint, yet does not have a DEFAULT constraint (value). The ALTER TABLE statement will fail in that case if the table has any rows in it. The solution is to either remove the NOT NULL constraint from the new column, or provide a DEFAULT constraint for it.

Recourse

Answer 8

Use:

-- Add a column with a default DateTime  
-- to capture when each record is added.

ALTER TABLE myTableName  
ADD RecordAddedDate SMALLDATETIME NULL DEFAULT (GETDATE())  
GO 

Intergrade

Answer 9

If you want to add multiple columns you can do it this way for example:

ALTER TABLE YourTable
    ADD Column1 INT NOT NULL DEFAULT 0,
        Column2 INT NOT NULL DEFAULT 1,
        Column3 VARCHAR(50) DEFAULT 'Hello'
GO

Faerie

Answer 10

To add a column to an existing database table with a default value, we can use:

ALTER TABLE [dbo.table_name]
    ADD [Column_Name] BIT NOT NULL
Default ( 0 )

Here is another way to add a column to an existing database table with a default value.

A much more thorough SQL script to add a column with a default value is below including checking if the column exists before adding it also checkin the constraint and dropping it if there is one. This script also names the constraint so we can have a nice naming convention (I like DF_) and if not SQL will give us a constraint with a name which has a randomly generated number; so it's nice to be able to name the constraint too.

-------------------------------------------------------------------------
-- Drop COLUMN
-- Name of Column: Column_EmployeeName
-- Name of Table: table_Emplyee
--------------------------------------------------------------------------
IF EXISTS (
            SELECT 1
            FROM INFORMATION_SCHEMA.COLUMNS
            WHERE TABLE_NAME = 'table_Emplyee'
              AND COLUMN_NAME = 'Column_EmployeeName'
           )
    BEGIN

        IF EXISTS ( SELECT 1
                    FROM sys.default_constraints
                    WHERE object_id = OBJECT_ID('[dbo].[DF_table_Emplyee_Column_EmployeeName]')
                      AND parent_object_id = OBJECT_ID('[dbo].[table_Emplyee]')
                  )
            BEGIN
                ------  DROP Contraint

                ALTER TABLE [dbo].[table_Emplyee] DROP CONSTRAINT [DF_table_Emplyee_Column_EmployeeName]
            PRINT '[DF_table_Emplyee_Column_EmployeeName] was dropped'
            END
     --    -----   DROP Column   -----------------------------------------------------------------
        ALTER TABLE [dbo].table_Emplyee
            DROP COLUMN Column_EmployeeName
        PRINT 'Column Column_EmployeeName in images table was dropped'
    END

--------------------------------------------------------------------------
-- ADD  COLUMN Column_EmployeeName IN table_Emplyee table
--------------------------------------------------------------------------
IF NOT EXISTS (
                SELECT 1
                FROM INFORMATION_SCHEMA.COLUMNS
                WHERE TABLE_NAME = 'table_Emplyee'
                  AND COLUMN_NAME = 'Column_EmployeeName'
               )
    BEGIN
    ----- ADD Column & Contraint
        ALTER TABLE dbo.table_Emplyee
            ADD Column_EmployeeName BIT   NOT NULL
            CONSTRAINT [DF_table_Emplyee_Column_EmployeeName]  DEFAULT (0)
        PRINT 'Column [DF_table_Emplyee_Column_EmployeeName] in table_Emplyee table was Added'
        PRINT 'Contraint [DF_table_Emplyee_Column_EmployeeName] was Added'
     END

GO

These are two ways to add a column to an existing database table with a default value.

Santo

Answer 11

Use:

ALTER TABLE {TABLENAME} 
ADD {COLUMNNAME} {TYPE} {NULL|NOT NULL} 
CONSTRAINT {CONSTRAINT_NAME} DEFAULT {DEFAULT_VALUE}

Reference: ALTER TABLE (Transact-SQL) (MSDN)

Scalp

Answer 12

You can do the thing with T-SQL in the following way.

 ALTER TABLE {TABLENAME}
 ADD {COLUMNNAME} {TYPE} {NULL|NOT NULL}
 CONSTRAINT {CONSTRAINT_NAME} DEFAULT {DEFAULT_VALUE}

As well as you can use SQL Server Management Studio also by right clicking table in the Design menu, setting the default value to table.

And furthermore, if you want to add the same column (if it does not exists) to all tables in database, then use:

 USE AdventureWorks;
 EXEC sp_msforeachtable
'PRINT ''ALTER TABLE ? ADD Date_Created DATETIME DEFAULT GETDATE();''' ;

Kooky

Answer 13

In SQL Server 2008-R2, I go to the design mode - in a test database - and add my two columns using the designer and made the settings with the GUI, and then the infamous Right-Click gives the option "Generate Change Script"!

Bang up pops a little window with, you guessed it, the properly formatted guaranteed-to-work change script. Hit the easy button.

Rochellerochemont

Answer 14

Alternatively, you can add a default without having to explicitly name the constraint:

ALTER TABLE [schema].[tablename] ADD  DEFAULT ((0)) FOR [columnname]

If you have an issue with existing default constraints when creating this constraint then they can be removed by:

alter table [schema].[tablename] drop constraint [constraintname]

Metrics

Answer 15

This can be done in the SSMS GUI as well. I show a default date below but the default value can be whatever, of course.

1. Put your table in design view (Right click on the table in object explorer->Design)
2. Add a column to the table (or click on the column you want to update if it already exists)
3. In Column Properties below, enter (getdate()) or 'abc' or 0 or whatever value you want in Default Value or Binding field as pictured below:

Oral

This feature is buggy in the 18.1 version of SSMS. I did that on a nvarchar, entered 'vision' in the Default Value or Bindung , saved but it didn't insert my string to new entities. I went back to the dialog and found the entry in the field being altered to ('vision') – Perfervid

Answer 16

ALTER TABLE ADD ColumnName {Column_Type} Constraint

The MSDN article ALTER TABLE (Transact-SQL) has all of the alter table syntax.

Bergeron

Answer 17

Example:

ALTER TABLE [Employees] ADD Seniority int not null default 0 GO

Vapory

Answer 18

Example:

ALTER TABLE tes 
ADD ssd  NUMBER   DEFAULT '0';

Leisha

Answer 19

First create a table with name student:

CREATE TABLE STUDENT (STUDENT_ID INT NOT NULL)

Add one column to it:

ALTER TABLE STUDENT 
ADD STUDENT_NAME INT NOT NULL DEFAULT(0)

SELECT * 
FROM STUDENT

The table is created and a column is added to an existing table with a default value.

Eugenie

Answer 20

This has a lot of answers, but I feel the need to add this extended method. This seems a lot longer, but it is extremely useful if you're adding a NOT NULL field to a table with millions of rows in an active database.

ALTER TABLE {schemaName}.{tableName}
    ADD {columnName} {datatype} NULL
    CONSTRAINT {constraintName} DEFAULT {DefaultValue}

UPDATE {schemaName}.{tableName}
    SET {columnName} = {DefaultValue}
    WHERE {columName} IS NULL

ALTER TABLE {schemaName}.{tableName}
    ALTER COLUMN {columnName} {datatype} NOT NULL

What this will do is add the column as a nullable field and with the default value, update all fields to the default value (or you can assign more meaningful values), and finally it will change the column to be NOT NULL.

The reason for this is if you update a large scale table and add a new not null field it has to write to every single row and hereby will lock out the entire table as it adds the column and then writes all the values.

This method will add the nullable column which operates a lot faster by itself, then fills the data before setting the not null status.

I've found that doing the entire thing in one statement will lock out one of our more active tables for 4-8 minutes and quite often I have killed the process. This method each part usually takes only a few seconds and causes minimal locking.

Additionally, if you have a table in the area of billions of rows it may be worth batching the update like so:

WHILE 1=1
BEGIN
    UPDATE TOP (1000000) {schemaName}.{tableName}
        SET {columnName} = {DefaultValue}
        WHERE {columName} IS NULL

    IF @@ROWCOUNT < 1000000
        BREAK;
END

Snavely

Answer 21

This is for SQL Server:

ALTER TABLE TableName
ADD ColumnName (type) -- NULL OR NOT NULL
DEFAULT (default value)
WITH VALUES

Example:

ALTER TABLE Activities
ADD status int NOT NULL DEFAULT (0)
WITH VALUES

If you want to add constraints then:

ALTER TABLE Table_1
ADD row3 int NOT NULL
CONSTRAINT CONSTRAINT_NAME DEFAULT (0)
WITH VALUES

Byroad

Answer 22

Try this

ALTER TABLE Product
ADD ProductID INT NOT NULL DEFAULT(1)
GO

Guarantee

Answer 23

SQL Server + Alter Table + Add Column + Default Value uniqueidentifier

ALTER TABLE Product 
ADD ReferenceID uniqueidentifier not null 
default (cast(cast(0 as binary) as uniqueidentifier))

Mossbunker

Answer 24

--Adding Value with Default Value
ALTER TABLE TestTable
ADD ThirdCol INT NOT NULL DEFAULT(0)
GO

Urticaceous

Answer 25

IF NOT EXISTS (
    SELECT * FROM INFORMATION_SCHEMA.COLUMNS
    WHERE TABLE_NAME ='TABLENAME' AND COLUMN_NAME = 'COLUMNNAME'
)
BEGIN
    ALTER TABLE TABLENAME ADD COLUMNNAME Nvarchar(MAX) Not Null default
END

That

Answer 26

Add a new column to a table:

ALTER TABLE [table]
ADD Column1 Datatype

For example,

ALTER TABLE [test]
ADD ID Int

If the user wants to make it auto incremented then:

ALTER TABLE [test]
ADD ID Int IDENTITY(1,1) NOT NULL

Ladder

Answer 27

There are 2 different ways to address this problem.
Both add a default value but add a totally different meaning to the problem statement here.

Let's start with creating some sample data.

Create Sample Data

CREATE TABLE ExistingTable (ID INT)
GO
INSERT INTO ExistingTable (ID)
VALUES (1), (2), (3)
GO
SELECT *
FROM ExistingTable

1. Add Columns with Default Value for Future Inserts

ALTER TABLE ExistingTable
ADD ColWithDefault VARCHAR(10) DEFAULT 'Hi'
GO

So now, as we have added a default column when we are inserting a new record, it will default its value to 'Hi' if the value is not provided.

INSERT INTO ExistingTable(ID)
VALUES (4)
GO
Select * from ExistingTable
GO

Well, this addresses our problem to have default value, but here is a catch to the problem. What if we want to have a default value in all the columns, not just the future inserts?

For this, we have Method 2.

2. Add Column with Default Value for ALL Inserts

ALTER TABLE ExistingTable
ADD DefaultColWithVal VARCHAR(10) DEFAULT 'DefaultAll'
WITH VALUES
GO
Select * from ExistingTable
GO

The following script will add a new column with a default value in every possible scenario.

Hyperthermia

Answer 28

Try with the below query:

ALTER TABLE MyTable
ADD MyNewColumn DataType DEFAULT DefaultValue

This will add a new column into the Table.

Crayfish

Answer 29

This can be done by the below code.

CREATE TABLE TestTable
    (FirstCol INT NOT NULL)
    GO
    ------------------------------
    -- Option 1
    ------------------------------
    -- Adding New Column
    ALTER TABLE TestTable
    ADD SecondCol INT
    GO
    -- Updating it with Default
    UPDATE TestTable
    SET SecondCol = 0
    GO
    -- Alter
    ALTER TABLE TestTable
    ALTER COLUMN SecondCol INT NOT NULL
    GO

Vaporish

Answer 30

Well, I now have some modification to my previous answer. I have noticed that none of the answers mentioned IF NOT EXISTS. So I am going to provide a new solution of it as I have faced some problems altering the table.

IF NOT EXISTS (SELECT * FROM INFORMATION_SCHEMA.columns WHERE table_name = 'TaskSheet' AND column_name = 'IsBilledToClient')
BEGIN
ALTER TABLE dbo.TaskSheet ADD
 IsBilledToClient bit NOT NULL DEFAULT ((1))
END
GO

Here TaskSheet is the particular table name and IsBilledToClient is the new column which you are going to insert and 1 the default value. That means in the new column what will be the value of the existing rows, therefore one will be set automatically there. However, you can change as you wish with the respect of the column type like I have used BIT, so I put in default value 1.

I suggest the above system, because I have faced a problem. So what is the problem? The problem is, if the IsBilledToClient column does exists in the table table then if you execute only the portion of the code given below you will see an error in the SQL server Query builder. But if it does not exist then for the first time there will be no error when executing.

ALTER TABLE {TABLENAME}
ADD {COLUMNNAME} {TYPE} {NULL|NOT NULL}
CONSTRAINT {CONSTRAINT_NAME} DEFAULT {DEFAULT_VALUE}
[WITH VALUES]

Microphone

Answer 31

ALTER TABLE <YOUR_TABLENAME>
ADD <YOUR_COLUMNNAME> <DATATYPE> <NULL|NOT NULL> 
ADD CONSTRAINT <CONSTRAINT_NAME>   ----OPTIONAL
DEFAULT <DEFAULT_VALUE>

If you are not giving constrain name then sql server use default name for this.

Example:-

ALTER TABLE TEMP_TABLENAME
ADD COLUMN1 NUMERIC(10,0) NOT NULL
ADD CONSTRAINT ABCDE   ----OPTIONAL
DEFAULT (0)

Laparotomy

Answer 32

ALTER TABLE tbl_table ADD int_column int NOT NULL DEFAULT(0)

From this query you can add a column of datatype integer with default value 0.

Horaciohorae

Answer 33

Right click on the table name and click on Design, click under the last column name and enter Column Name, Data Type, Allow Nulls.

Then in bottom of page set a default value or binding : something like '1' for string or 1 for int.

Kilmarnock

Answer 34

If the default is Null, then:

1. In SQL Server, open the tree of the targeted table
2. Right click "Columns" ==> New Column
3. Type the column Name, Select Type, and Check the Allow Nulls Checkbox
4. From the Menu Bar, click Save

Done!

Foucquet

Answer 35

You can use this query:

ALTER TABLE tableName ADD ColumnName datatype DEFAULT DefaultValue;

Philis

Answer 36

step-1. FIRST YOU HAVE TO ALTER TABLE WITH ADD a FIELD

alter table table_name add field field_name data_type

step-2 CREATE DEFAULT

USE data_base_name;
GO
CREATE DEFAULT default_name AS 'default_value';

step-3 THEN YOU HAVE TO EXECUTE THIS PROCEDURE

exec sp_bindefault 'default_name' , 'schema_name.table_name.field_name'

example -

USE master;
GO
EXEC sp_bindefault 'today', 'HumanResources.Employee.HireDate';

Rescission

Answer 37

--Adding New Column with Default Value
ALTER TABLE TABLENAME 
ADD COLUMNNAME DATATYPE NULL|NOT NULL DEFAULT (DEFAULT_VALUE)

OR

--Adding CONSTRAINT And Set Default Value on Column
ALTER TABLE TABLENAME ADD  CONSTRAINT [CONSTRAINT_Name]  DEFAULT 
(DEFAULT_VALUE) FOR [COLUMNNAME]

Sinusoidal

Answer 38

SQL Server + Alter Table + Add Column + Default Value uniqueidentifier...

ALTER TABLE [TABLENAME] ADD MyNewColumn INT not null default 0 GO

Suction

Answer 39

ALTER TABLE Table1 ADD Col3 INT NOT NULL DEFAULT(0)

Spiker

Answer 40

In SQL Server, you can use below template:

ALTER TABLE {tablename}
ADD 
    {columnname} {datatype} DEFAULT {default_value}

For example, to add a new column [Column1] of data type int with default value = 1 into an existing table [Table1] , you can use below query:

ALTER TABLE [Table1]
ADD 
    [Column1] INT DEFAULT 1

Riplex

Answer 41

OFFLINE and ONLINE pertain to how to ALTER table performed on NDB Cluster Tables. NDB Cluster supports online ALTER TABLE operations using the ALGORITHM=INPLACE syntax in MySQL NDB Cluster 7.3 and later. NDB Cluster also supports an older syntax specific to NDB that uses the ONLINE and OFFLINE keywords. These keywords are deprecated beginning with MySQL NDB Cluster 7.3; they continue to be supported in MySQL NDB Cluster 7.4 but are subject to removal in a future version of NDB Cluster.

IGNORE pertains to how the ALTER statement will deal with duplicate value in the column that has newly added constraint UNIQUE. If IGNORE is not specified, ALTER will fail and not be applied. If IGNORE is specified, the first row of all duplicate rows is kept, the reset deleted and the ALTER applied.

The ALTER_SPECIFICATION would be what you are changing. what column or index you are adding, dropping or modifying, or what constraints you are applying on the column.

ALTER [ONLINE | OFFLINE] [IGNORE] TABLE tbl_name
       alter_specification [, alter_specification] ...

    alter_specification:
        ...
        ADD [COLUMN] (col_name column_definition,...)
        ...

Eg: ALTER TABLE table1 ADD COLUMN foo INT DEFAULT 0;

Unessential

Answer 42

ALTER table dataset.tablename ADD column_current_ind integer DEFAULT 0

Deroo

Answer 43

alter table TBL add col datatype default null after col2;

e.g:- alter table vendors add updatedBy varchar(255) default not null after isActive;

Eyla

Answer 44

SYNTAX:

ALTER TABLE {TABLENAME} 
ADD {COLUMNNAME} {TYPE} {NULL|NOT NULL} 
CONSTRAINT {CONSTRAINT_NAME} DEFAULT {DEFAULT_VALUE}
WITH VALUES

EXAMPLE:

ALTER TABLE Admin_Master 
ADD Can_View_Password  BIT NULL 
CONSTRAINT DF_Admin_Master_Can_View_Password DEFAULT (1)
WITH VALUES 

Hydrochloride

Answer 45

For Oracle Toad users:

 ALTER TABLE YOUR_SCHEMA.YOUR_TABLENAME ADD YOUR_COLUMNNAME VARCHAR2(100 CHAR);
COOMMIT;

Steve

Those "toad users" may ask. what this coomit is and why they can't find it in the docs. – Filippa