[Dovecot] dovecot and virtual mailbox - suggestions please

I've setup postfix to delivered my mail to a maildir located at

/var/spool/virtual_mailboxes/mydomain.com/myuser

My postgresql database called 'mails' has a user table setup as follows:

CREATE TABLE users ( userid VARCHAR(128) NOT NULL, password VARCHAR(128), realname VARCHAR(128), uid INTEGER NOT NULL, gid INTEGER NOT NULL, home VARCHAR(128), mail VARCHAR(255), PRIMARY KEY (userid) );

What would the query look like in my dovecot-pgsql.conf file to retrieve the appropriate INBOX information?

mine currently looks like this. user_query = SELECT '/var/spool/virtual_mailboxes/'||home AS home, uid, gid FROM users WHERE userid = '%u'

The user authenticates fine via pop, yet I keeping getting the following error. -*ERR No INBOX for user*