多条插入拼接

  string sql = @"update a 
                            set a.M_ParentID=b.M_ParentID,
                            a.M_Name=b.M_Name,
                            a.M_Seq=b.M_Seq,
                            a.M_IsDel=b.M_IsDel
                            from SysMenu_BySchool a
                            inner join (";
            foreach (SysMenu_BySchoolEntity m in lstMenu)
            {
                sql += string.Format("select {0} ID,{1} as M_ParentID,'{2}' as M_Name,{3} as M_Seq,{4} as M_IsDel union ", m.ID, m.M_ParentID, Utils2.ValidChar(m.M_Name), m.M_Seq,m.M_IsDel.ToString());
            }
            sql = sql.TrimEnd(" union ".ToCharArray());
            sql += ") b on a.ID=b.ID";
            return dal.UpdateCommand(sql, null);