How to add new column with default value from existing column in Liquibase
<p>I'm using Postgres DB and for migration I'm using Liquibase.
I have an ORDERS table with the following columns:</p>

<pre><code>ID | DATE | NAME | CREATOR | ...
</code></pre>

<p>I need to add a new column which will hold the user who has last modified the order - this column should be not-nullable and should have default value which is the CREATOR.
For new orders I can solve the default value part of the business logic, <strong>but</strong> thing is I already have an existing orders and I need to set the default value when I create the new column.
Now, I know I can set a hard-coded <a href="http://www.liquibase.org/documentation/changes/add_default_value.html" rel="noreferrer">default value in Liquibase</a> - but is there a way I could add the default value based on some other column of that table (for each entity).</p>