After create table if you want to change default value for any column of table the we can use alter command in following way
Syntax
1 2 3 | alter table table_name alter column_name set default default_value; |
Example
1 2 3 | alter table student alter semester set default "first"; |
1 2 3 | alter table student alter address set default "Bhopal"; |
above query will set default value for column_name to provided default value.