Default columns for Trac query

defaultcols.py

# Adds a new `default_cols` option under [query] with a comma-separated list of default columns
# See http://trac-hacks.org/wiki/DefaultColsPlugin

from trac.core import *
from trac.web.main import IRequestFilter
from trac.config import ListOption

class DefaultCols(Component):
    implements(IRequestFilter)

    default_cols = ListOption('query', 'default_cols',  default=None,
                              doc="""List of columns to show in query unless defined by the query.""")

   # -- IRequestFilter                                                                                                                                       
    def pre_process_request(self, req, handler):
        if self.default_cols != None and req.path_info == '/query' and 'col' not in req.args:
            req.args['col'] = self.default_cols
        return handler

    def post_process_request(self, req, template, data, content_type):
        return template, data, content_type

There's work in progress at #10425 to get this functionality into core, but in the meanwhile you can use this plugin.