C# App คำสั่ง SQL ผมไล่แล้วไม่ได้อะครับช่วยดูให้ที

 "SELECT SID, Come, Number  FROM enroll LEFT JOIN (scan ON enroll.SID = scan.SID)where Codeno = '" + comboBox31.Text + "' and Groups = '" + comboBox32.Text + "'and Semester = '" + comboBox30.Text + "'and Years = '" + comboBox29.Text + "' order by SID asc";