Which country is the University of Oxford located?
University of Oxford refers to university_name = 'University of Oxford'; which country refers to country_name
SELECT T2.country_name FROM university AS T1 INNER JOIN country AS T2 ON T1.country_id = T2.id WHERE university_name = 'University of Oxford'
database name:db_id university
country table country Cols: id dtype integer, country name dtype text, 
ranking_system table ranking_system Cols: id dtype integer, system name dtype text, 
ranking_criteria table ranking_criteria Cols: id dtype integer, ranking system id dtype integer, criteria name dtype text, 
university table university Cols: id dtype integer, country id dtype integer, university name dtype text, 
university_ranking_year table university_ranking_year Cols: university id dtype integer, ranking criteria id dtype integer, year dtype integer, score dtype integer, 
university_year table university_year Cols: university id dtype integer, year dtype integer, number of students dtype integer, student staff ratio dtype real, pct internation student dtype integer, pct female students dtype integer, 
