拆分多行 CLOB 列 - Oracle PL/SQL

Question

我有一个 table，其中包含一个 CLOB 字段，其值由逗号分隔值的行组成。在输出中，我希望每一行都以特定值开头。我还想高效地提取一些逗号分隔值。

输入table（3行）：

id         my_clob
001        500,aaa,bbb
           500,ccc,ddd
           480,1,2,bad
           500,eee,fff
002        777,0,0,bad
003        500,yyy,zzz

目标输出（4 行）：

id         my_clob          line_num    line           second_val
001        500,aaa,bbb      1           500,aaa,bbb    aaa
           500,ccc,ddd
           480,1,2,bad
           500,eee,fff
001        500,aaa,bbb      2           500,ccc,ddd    ccc
           500,ccc,ddd
           480,1,2,bad
           500,eee,fff
001        500,aaa,bbb      3           500,eee,fff    eee
           500,ccc,ddd
           480,1,2,bad
           500,eee,fff
003        500,yyy,zzz      1           500,yyy,zzz    yyy

这与 , but in that case, there was a non-hidden character to split on. A related question 删除换行符非常相似。我想根据分隔这些行的任何字符进行拆分。我试过 chr(10) || chr(13) 和 [:space:]+ 的变体但没有成功

我的尝试：

SELECT 
   id
   ,my_clob
   ,level as line_num
   ,regexp_substr(my_clob,'^500,\S+', 1, level, 'm') as line 
   ,regexp_substr(
        regexp_substr(
            my_clob,'^500,\S+', 1, level, 'm'
        )
        ,'[^,]+', 1, 2
   ) as second_val
FROM tbl
CONNECT BY level <= regexp_count(my_clob, '^500,\S+', 1, 'm')
  and prior id = id
  and prior sys_guid() is not null

结果通常只从my_clob中的第一行导出，这取决于我如何调整匹配模式。

我指定这个'm'match_parameter，根据Oracle Docs：

'm' treats the source string as multiple lines. Oracle interprets the caret (^) and dollar sign ($) as the start and end, respectively, of any line anywhere in the source string

这些 regexp_*(my_clob, '^500,\S+', 1, 'm') 有什么问题吗？或者更好的是，有没有没有正则表达式的更高效的方法？

Answer 1

您可以按如下方式使用REGEXP：

SQL> -- sample data
SQL> with your_data(id,myclob) as
  2  (select 1, '500,aaa,bbb
  3             500,ccc,ddd
  4             480,1,2,bad
  5             500,eee,fff' from dual)
  6  -- Your query starts from here
  7  select id, myclob, line_num, lines as line,
  8  regexp_substr(lines,'[^,]+',1,2) as second_val
  9  from
 10    (select id, myclob, column_value as line_num,
 11  trim(regexp_substr(d.myclob,'.+',1,column_value,'m')) as lines
 12     from your_data d
 13     cross join table(cast(multiset(select level from dual
 14                                 connect by  level <= regexp_count(d.myclob,'$',1,'m'))
 15     as sys.OdciNumberList)) levels)
 16  where regexp_like(lines,'^[500]');

 ID MYCLOB                    LINE_NUM LINE            SECOND_VAL
--- ------------------------- -------- --------------- ----------
  1 500,aaa,bbb                      1 500,aaa,bbb     aaa
    500,ccc,ddd
    480,1,2,bad
    500,eee,fff

  1 500,aaa,bbb                      2 500,ccc,ddd     ccc
    500,ccc,ddd
    480,1,2,bad
    500,eee,fff

  1 500,aaa,bbb                      4 500,eee,fff     eee
    500,ccc,ddd
    480,1,2,bad
    500,eee,fff


SQL>

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