List the names of all the universities that have no less than 50,000 students in the year 2012.
have no less than 50,000 students refers to num_students > 50000; name of university refers to university_name;
SELECT T2.university_name FROM university_year AS T1 INNER JOIN university AS T2 ON T1.university_id = T2.id WHERE T1.num_students > 50000 AND T1.year = 2012
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, 
