如何在 Oracle 中拆分逗号分隔的字符串

Question

如何使用 SUBSTR 和 INSTR.

在 Oracle 中拆分逗号分隔的字符串

字符串 '20.4,12.5,3.5,0.2,0.2'.

我尝试使用以下代码，但我无法获取第二个逗号后的值。

SELECT substr('20.4,12.5,3.5,0.2,0.2',0,instr('20.4,12.5,3.5,0.2,0.2',',')-1) 
value FROM dual   -- 1. 20.4

对于第二个值，我在第二个逗号后得到整个字符串。

SELECT substr('20.4,12.5,3.5,0.2,0.2',instr('20.4,12.5,3.5,0.2,0.2',',')+1,instr('20.4,
12.5,3.5,0.2,0.2',',',2,2)-1) st FROM dual   -- result : 12.5,3.5,

我想要每个逗号后的值，比如

20.4

12.5

3.5等等。

Answer 1

基于https://blogs.oracle.com/aramamoo/how-to-split-comma-separated-string-and-pass-to-in-clause-of-select-statement：

首先，我们将形成一个查询，拆分这个逗号分隔的字符串并将各个字符串作为行给出。

SQL> select regexp_substr('20.4,12.5,3.5,0.2,0.2','[^,]+', 1, level) from dual
     connect by regexp_substr('20.4,12.5,3.5,0.2,0.2', '[^,]+', 1, level) is not null;


REGEXP_SUBSTR('20.4,1
---------------------
20.4                 
12.5                 
3.5                  
0.2                  
0.2

以上查询遍历逗号分隔的字符串，搜索逗号 (,)，然后通过将逗号视为分隔符来拆分字符串。它 returns 字符串作为一行，每当它遇到分隔符时。

Answer 2

You can also check for a specific occurrence, sample, ever second occurrence between comma.

SQL> select regexp_substr('20.4,12.5,3.5,0.2,0.2','[^,]+[^,]', 1,2 ) as 2nd_occur 
     from dual;

 ", 1,2 )" -- You can replace this query part to choose with occurrence you want, like 

 ", 1,3 )" -- for third occurrence.`


Output:

2nd_occur
---------
12.5

Answer 3

如果您的数据库中安装了 APEX 5.1 或更高版本，您可以使用 apex_string.split :

非常优雅地解决这个问题

select column_value
from table(apex_string.split('20.4,12.5,3.5,0.2,0.2', ','))

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