如何将分隔字符串拆分为 n(n-1)/2 到 Oracle SQL 中的组合？

Question

例如"red/green/blue"拆分成下面的

redred/greenred/green/blue

select * from table where column in('red','red/green','red/green/blue');

Answer 1

您可以将substr 和inst 组合用作：

with t as
(
select 'red/green/blue' as str from dual
)
select substr(str,1,instr(str,'/',1,1)-1) str1,
       substr(str,1,instr(str,'/',1,2)-1) str2,
       str as str_whole
  from t;

STR1    STR2        STR_WHOLE
----    ----------  --------------
red     red/green   red/green/blue

如果您想逐行显示，您可以通过添加 regexp_count 来使用以下样式：

with t as
(
select 'red/green/blue' as str from dual
)
select decode(sign(instr(str,'/',1,level)),1,substr(str,1,instr(str,'/',1,level)-1),str)
       as str
  from t
connect by level <= regexp_count(str,'/') + 1; 

STR 
--------------   
red     
red/green   
red/green/blue

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