Select unique sign occurrences as used here: http://cdb.io/15ekzYE

signselect.sql

SELECT 
    house,
    street_name,
    MIN(cartodb_id) AS cartodb_id,
    MIN(the_geom) AS the_geom, 
    MIN(the_geom_webmercator) AS the_geom_webmercator,
    MIN(text_on_sign) AS text_on_sign,
    MIN(text_occurrences) AS text_occurrences,
    MIN(rotation) AS rotation
FROM sign_application_filings
WHERE text_on_sign != ''
GROUP BY house, street_name