The goal of this study is to investigate the efficacy and safety of Canagliflozin (which is experimental) in children and adolescents ages 10 to 18 years old with Type 2 diabetes and poor control (i.e., an HbA1c of 6.5% to 10.5%). Study drug or placebo would be taken alone or with metformin or insulin as needed. Monitoring tests include blood, urine, physical exams, vital signs, blood sugar and ketone monitoring, diabetes management counseling.