SELECT xmltable.*
    FROM xmldata,
    XMLTABLE('//ROWS/ROW'
        PASSING data
            COLUMNS id int PATH '@id',
            ordinality FOR ORDINALITY,
            "COUNTRY_NAME" text,
            country_id text PATH 'COUNTRY_ID',
            size_sq_km float PATH 'SIZE[@unit = "sq_km"]',
            size_other text PATH 'concat(SIZE[@unit!="sq_km"], " ", SIZE[@unit!="sq_km"]/@unit)',
            premier_name text PATH 'PREMIER_NAME' DEFAULT 'not specified');