SELECT A.*,IFNULL(B.JoinType,0) AS JoinType,IFNULL(B.TargetJoinType,0) AS TargetJoinType,IFNULL(B.StartClassHours,0) AS StartClassHours,IFNULL(C.CourseName,'') AS CourseName
SELECT A.*,IFNULL(B.JoinType,0) AS JoinType,IFNULL(B.TargetJoinType,0) AS TargetJoinType,IFNULL(B.StartClassHours,0) AS StartClassHours,IFNULL(C.CourseName,'') AS CourseName