oracle分组后合并其中一个字段

来自https://blog.csdn.net/gaoyao99409/article/details/19003729

select m.parent_id,
               m.start_date,
               wmsys.wm_concat(m.cleck_name) As name,
               wmsys.wm_concat(m.userId) As userId,
               max(rowid) as rid
          from (select t.parent_id,
                       to_char(t.start_date, 'yyyy-MM-dd') start_date,
                       s.cleck_name,
                       s.user_orderby,
                       t.sche_type,
                       s.id as userId
                  from oa_assistant_schedulerplan t, s_user s
                 where t.user_id = s.id(+)
                   and t.sche_type != '1'
                   and t.parent_id is not null
                 order by s.user_orderby) m

         group by m.parent_id, m.start_date

按parent_id和start_date分组后合并每个组的cleck_name和userId

另一个实例：

来自http://blog.sina.com.cn/s/blog_56d8ea900100zlwv.html

数据库的结构如下:

no   item

01    AA
01    BB
02    CC
02    DD
02    EE
03    FF
04    GG
04    HH

希望将no相同的列整合为一条记录如下
no   items
01   AA,BB
02   CC,DD,EE
03    FF
04   GG,HH


MYSQL中，直接有group_contact函数了，如下：
  select id,group_contact(items) from TABLE group by id

而oracle中，对应的有wm_contact,摘抄例子如下：
select id,wmsys.wm_concat(items) name from table
group by id;