在开始演示之前我们需要新建一张表出来：
with temp as(
select 'China' nation,'Guangzhou' city from dual union all
select 'China' nation,'Shanghai' city from dual union all
select 'China' nation,'Beijing' city from dual union all
select 'USA' nation,'New York' city from dual union all
select 'USA' nation,'Bostom' city from dual union all
select 'Japan' nation,'Tokyo' city from dual
)
接着我们可以使用listagg函数来进行演示：
select nation,listagg(city,',') within GROUP (order by city)
from temp
group by nation ;
效果如下：
最基础的用法如下：
LISTAGG(XXX,XXX) WITHIN GROUP( ORDER BY XXX)
with temp as(
select 500 population,'China' nation,'Guangzhou' city from dual union all
select 1500 population,'Shanghai' city from dual union all
select 500 population,'Beijing' city from dual union all
select 1000 population,'USA' nation,'New York' city from dual union all
select 500 population,'Bostom' city from dual union all
select 500 population,'Japan' nation,'Tokyo' city from dual
)
listagg() + over()用法的演示：
select population,
nation,
city,
listagg(city,') within GROUP (order by city) over (partition by nation) rank
from temp
PS：在listagg(city,'/')这里我们可以使用我们想要的分隔符。
