Can I change a column from NOT NULL to NULL without dropping it?

ALTER TABLE myTable ALTER COLUMN myColumn {DataType} NULL

where {DataType} is the current data type of that column (For example int or varchar(10))

The syntax is very based on database service

SQL Server / MS Access:

ALTER TABLE table_name
ALTER COLUMN column_name datatype NULL;

My SQL / Oracle (prior version 10G):

ALTER TABLE table_name
MODIFY COLUMN column_name datatype NULL;

Oracle 10G and later:

ALTER TABLE table_name
MODIFY column_name datatype NULL;

if you want to set a default value then:

ALTER TABLE table_name
ALTER COLUMN column_name datatype DEFAULT default_value;

Sure you can.

ALTER TABLE myTable ALTER COLUMN myColumn int NULL

Just substitute int for whatever datatype your column is.

Related