如何获得sql的最新年份

sql = "select scn,name,imp_flg,cg_desc from"
                    +" (select  vesvoy.scn, vessel.name,'I' as imp_flg,cargotype.description as cg_desc  from vesvoy"
                    +" join vessel on vesvoy.vessel_id = vessel.id "
                    +" join vesvoy_mf on vesvoy.id = vesvoy_mf.id_1"
                    +" join mf_bl on vesvoy_mf.id_2 = mf_bl.id_1"
                    +" join bl on mf_bl.id_2 = bl.id "
                    +" join blitem on blitem.master_id = bl.id"
                    +" join cargotype on blitem.cg_type_id = cargotype.id"
                    + " where bl.inv_flg<>'1' and year(vesvoy.exp_arr_dt_tm) in year(CURRENT_TIMESTAMP) , year(CURRENT_TIMESTAMP)-1"
                    +" union"
                    +" select   vesvoy.scn, vessel.name,'E' as imp_flg,cargotype.description as cg_desc"
                    +" from vesvoy"
                    +" join vessel on vesvoy.vessel_id = vessel.id "
                    +" join vesvoy_so on vesvoy.id = vesvoy_so.id_1"
                    +" join so_sso on vesvoy_so.id_2 = so_sso.id_1"
                    +" join sso on so_sso.id_2 = sso.id "
                    +" join ssoitem on ssoitem.master_id = sso.id"
                    +" join cargotype on ssoitem.cg_type_id = cargotype.id"
                    + " where sso.inv_flg<>'1' and  year(vesvoy.exp_arr_dt_tm) in year(CURRENT_TIMESTAMP) , year(CURRENT_TIMESTAMP)-1) as a ";
sql = "select scn,name,imp_flg,cg_desc from"