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.
To get all tables with columns columnA
or ColumnB
in the database YourDatabase
:
SELECT DISTINCT TABLE_NAME
FROM INFORMATION_SCHEMA.COLUMNS
WHERE COLUMN_NAME IN ('columnA','ColumnB')
AND TABLE_SCHEMA='YourDatabase';
Best Solution
If you are unsure the number of phone number you will need per record, you might want to have a phone numbers table. It may be easier for you to run a php script to update the database like so (I'm assuming you don't sanitize your phone numbers to a specific format and that you use INNODB):
Create the phone number's table:
Then write a php script to split the existing field data and create inserts into the new table.
EDIT: As mentioned below in my comment, you could have a backwards compatable view that would still have the phone numbers concat together until you can update everything: