Redshift - How to remove NOT NULL constraint?

Question

Since Redshift does not support ALTER COLUMN, I would like to know if it\'s possible to remove the NOT NULL constraints from columns in Redshift.

Answer 1

You cannot alter the table.

There is an alternative approach. You can create a new column with NULL constraint. Copy the values from your old column to this new column and then drop the old column.

Something like this:

ALTER TABLE table1 ADD COLUMN somecolumn (definition as per your reqm);
UPDATE table1 SET somecolumn = oldcolumn;
ALTER TABLE table1 DROP COLUMN oldcolumn;
ALTER TABLE table1 RENAME COLUMN somecolumn TO oldcolumn;