For instance "Presidential General Election, State Results, 2008" from
http://www.nationalatlas.gov/atlasftp.html?openChapters=chphist%2Cchpref%2Cchpgeol#chpgeol
Note: Here I found out that database names with numbers are best avoided in TileMill < 0.7. On my TileMill 0.6 installation I could add the table name 'election2008' but I could not use it in a subquery.
This is a coloring of the map by voting results favoring democrats (somewhat naive because an absence of a democrat vote assumes a republican vote).
https://skitch.com/alexbarth/gjnju/tilemill
#results {
polygon-fill: #f5f5f5;
}
#results::fill[zoom>=0] {
[percent_de > '70.0']{ polygon-fill:#0a66c2; }
[percent_de > '60.0'][percent_de <= '70.0']{ polygon-fill:#2f53a5; }
[percent_de > '50.0'][percent_de <= '60.0']{ polygon-fill:#544189; }
[percent_de > '40.0'][percent_de <= '50.0']{ polygon-fill:#782f6c; }
[percent_de > '30.0'][percent_de <= '40.0']{ polygon-fill:#9d1c4f; }
[percent_de <= '30.0']{ polygon-fill:#c20a33; }
[percent_de = null]{ polygon-fill:#f5f5f5; }
}
Will White explains how to use SQLite's attach feature in TileMill. This is useful for joining SQLite databases containing the data to be displayed to SQLite databases containing the geometry to use.
http://developmentseed.org/blog/2011/aug/30/tilemill-05-adds-sqlite-datasource-support/