Provide the number of staff at the University of Auckland in 2015.
University of Auckland refers to university_name = 'University of Auckland'; in 2015 refers to year = 2015; number of staff refers to DIVIDE(num_students, student_staff_ratio)
SELECT CAST(SUM(T1.num_students) AS REAL) / SUM(T1.student_staff_ratio) FROM university_year AS T1 INNER JOIN university AS T2 ON T1.university_id = T2.id WHERE T2.university_name = 'University of Auckland' AND T1.year = 2015
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, 
