What elisp or macro magic can make this text transformation?

I have a set of SQL statements formatted like so:

INSERT INTO reports.workload (workload_id,event_time,event_type_id,agent_id) VALUES 
                             (-42000,'2010-02-23 07:30:38.941436',1,NULL);

Right now, the VALUES tuple is aligned at the start with the column name tuple. However, what I want is to have the tuple's elements aligned as well, like so:

INSERT INTO reports.workload (workload_id,event_time,                  event_type_id,agent_id) VALUES 
                             (-42000,开发者_StackOverflow中文版     '2010-02-23 07:30:38.941436',1            ,NULL);

My elisp-fu and regexp-fu are moderate, but not sufficient to this task. How can I do this?

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Select the region you'd like to align, and type C-u C-x \ (that is a shortcut for align-regexp). Choose \(,\) as regex pattern and repeat it throughout line.

For more on text align, see chapter AlignCommands in EmacsWiki.