出现单个逗号时拆分字符串，Oracle 中出现多个逗号时不拆分

如何解决出现单个逗号时拆分字符串，Oracle 中出现多个逗号时不拆分

--case#1

select '1,2,3,4,5,6' from dual; 

--case#2

select q'[1aaaaaa,bbb,bbbb (cccc,ccccc) 20,20-09-30 11:11:11 (dddddddd): below eeeeeee is ddddd of teh dddd. ajhvajshbfjasbhfjkabsdfkjabsfkljbaaksjfka . 569716476@@asdasa asdasdi (asfasfasf) 2020-09-30 22:22:27 (sdfsdfal): As per sdfsdfsdfg sdfm: sds the below is a sdfsdf@@@@3**** sd sd sdd sdffve sdffin with sdf ��� the below is correct. the "sdfd" sds tsd sdfe fsI as sdfL. hsdfe we do not sdffte fsw dsddDs123**** just new sdfsdng ssdfsds.@@sdfsda sdfsdni (sdffdsdUP) 2020-09-23 22:31:54 (sdffsdal): sdil zxct cx Gzxcz zxcc: zxcc/zxI-Jcxz- cx zxccx***zxccc rzxcczxc***. 569zxc476@@zxccxi zxcxzze (zxcczxzxc) 2020-02-28 22:21:26,(zxtezxcxz) 03/28-As per zxcc,zxzxx by cx cxcx zxzz is zxcxzz zxcxz zxcc. zxc zx]'
from dual; 

--case#3

Please just copy paste the string present in Case#2 several times so that the overall length increase 4000 characters and try you solution.

这个字符串应该在单个逗号出现时拆分，并且不应该在多次出现逗号时拆分，例如双/三等。

另外，如果有人可以用 12345 之类的字符串替换上面的多个逗号，那么它对我有用。不要替换单个逗号

注意上面的字符串来自一个 CLOB 列，所以需要一个高效的查询，它应该占用更少的 CPU。

o/p:
1
2,2
3
4,4
5,5     -- NOTE: this has multiple commas with space
6

解决方法

从 Oracle 11gR2 开始，您可以使用：

WITH strings (value,end_pos,term) AS (
  SELECT value,REGEXP_INSTR(value,'((\d+(,*){2,})*\d+)(,|$)',1,1),REGEXP_SUBSTR(value,NULL,1)
  FROM   table_name
UNION ALL
  SELECT value,1)
  FROM   strings
  WHERE  end_pos > 0
)
SELECT term
FROM   strings
WHERE  end_pos > 0;

对于样本数据：

CREATE TABLE table_name ( value ) AS
select '1,2,3,4,5,6' from dual;

输出：

期限
1
2,2
3
4,4
5,5
6

---

可能适用于早期版本的替代方法是：

SELECT RTRIM(
         REGEXP_SUBSTR(
           t.value,l.COLUMN_VALUE
         ),','
       ) AS term
FROM   table_name t
       CROSS JOIN
       TABLE(
         CAST(
           MULTISET(
             SELECT LEVEL
             FROM   DUAL
             CONNECT BY
                    REGEXP_INSTR(
                      t.value,LEVEL
                    ) > 0
           )
           AS SYS.ODCINUMBERLIST
         )
       ) l

sqlfiddle here