Sql 如何消除列中的重复数据

我想消除重复和显示一次

比如说

SELECT 'apple, apple, orange'
FROM dual;

我想展示一下

apple, orange

再举一个例子

SELECT 'apple, apple, apple, apple,'
FROM dual;

我只是想展示一下

apple

此代码显示

with data as
(
  select 'apple, apple, apple, apple' col from dual
)
select listagg(col, ',') within group(order by 1) col
  from (
        select distinct regexp_substr(col, '[^,]+', 1, level) col
          from data
        connect by level <= regexp_count(col, ',')
       )

---

这样可以消除重复项：

输出

正如你所看到的，你会得到一个空值，因为额外的逗号

---

as中有几个选项：

只需将数字替换为输入“apple，apple，orange”

使用trim和distinct with regexp函数，这对于获得所需结果非常重要

select listagg(str,',') within group (order by 0) as Result
from
(
 select distinct trim(regexp_substr('apple, apple, orange','[^,]+', 1, level)) as str
   from dual
connect by level <= regexp_count('apple, apple, orange',',') + 1
);

---

为什么标题中有日期？@user7294900抱歉，这意味着重复数据您可以编辑您的问题title@JuanCarlosOropeza. 谢谢我做到了！！！你能检查一下你对rextester的查询吗？他没有给我预期的输出

with data as
 (
 select 

'5,5,5,5,6,6,5,5,5,6,7,4,1,2,1,4,7,2' col from dual
)
 select listagg(col, ',') within group(order by 1) col
 from (
    select distinct regexp_substr(col, '[^,]+', 1, level) col
    from data
    connect by level <= regexp_count(col, ',')
   )

select listagg(str,',') within group (order by 0) as Result
from
(
 select distinct trim(regexp_substr('apple, apple, orange','[^,]+', 1, level)) as str
   from dual
connect by level <= regexp_count('apple, apple, orange',',') + 1
);