sql - 在 pl/sql 中标记字符串并获得唯一标记？

Question

我需要在 pl/sql 中标记字符串并仅返回唯一标记。我见过将字符串标记化的示例，但没有一个会返回唯一标记。

例如查询 -

select tokenize('hi you person person', ' ') as col1 from dual;

应该返回 TOKEN_LIST('hi','you','person')

代替 TOKEN_LIST('hi','you','person','person')

Answer 1

with t as (select 'aaaa bbbb cccc dddd eeee ffff aaaa' as txt from dual)
-- end of sample data
select DISTINCT REGEXP_SUBSTR (txt, '[^[:space:]]+', 1, level) as word
from t
connect by level <= length(regexp_replace(txt,'[^[:space:]]+'))+1;

上面的脚本产生以下结果:

WORD
dddd
eeee
bbbb
ffff
cccc
aaaa

这个想法是无耻地从OTN Community answer偷来的.

SQL Fiddle