Add a column to a hypertable

You add a column to a hypertable using the ALTER TABLE command. In this example, the hypertable is named conditions and the new column is named humidity:

If the column you are adding has the default value set to NULL, or has no default value, then adding a column is relatively fast. If you set the default to a non-null value, it takes longer, because it needs to fill in this value for all existing rows of all existing chunks.