问这句sql语句

[asphp]

select distinct chu_booking.*,to_char(bok_tmsid) AS tmsid,bok_courtno AS courtno FROM chu_booking WHERE bok_facid = '0001' AND bok_bokdate = to_date('26/02/2004', 'dd/mm/yyyy') AND bok_status not in ('V', 'R') UNION Select distinct chu_booking.* ,to_char(chu_orderdtl.cod_tmsid) AS tmsid, bok_courtno AS courtno FROM chu_booking, chu_order,chu_orderdtl WHERE bok_facid = '0001' AND bok_bokid = cor_bokid(+) and cor_orderno=cod_orderno and cod_tmsid(+)>bok_tmsid AND bok_bokdate = to_date('26/02/2004', 'dd/mm/yyyy') AND bok_status not in ('V', 'R') ORDER BY tmsid, courtno
这里面有一个cod_tmsid(+)>bok_tmsid是什么意思？