Merge shapefiles using ogr2ogr and retrieve the attributes of both

I have two shapefiles that I want merge (overlay/intersect) having in the destination the attributes of the two sources file.

ogr2ogr file_merged.shp tl_2010_us_uac10_conus_albersUA.shp

ogr2ogr -update -append file_merged.shp tabblock2010_10_pophu.shp -nln file_merged

In this way I obtain the polygons of the two shapes, but I lose the attributes of the tabblock2010_10_pophu.shp.

My final aim is then make an SQL statement where I can retrieve polygon in common in the both shapes.

Any suggestions??