徐 哈哈@joker_xuChinaFollow BadgesProblem SolvingSql CertificationsCertificate: Problem Solving (Basic)VerifiedskillCertificate: Problem Solving (Intermediate)VerifiedskillCertificate: Problem Solving (Advanced)VerifiedskillWork Experiencejoker_xu has not updated employment details yet.Educationjoker_xu has not updated education details yet.