Returns the geometry which is the topological union of the specified geometric objects. Using Oracle Retorna la geometría que es la unión topologica de los objetos geométricos especificados. Usando Oracle, must be taken into account that the value of tolerance can affect the topology of the obtained geometry.

1 geo.aggrUnion

    <geometry_column /> *
       <geo.aggrUnion pg_collect='y'>a.type, a.geometry_col</geo.aggrUnion>
    <from table='buildings' alias='a' >