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sqlregexoracle-databaseregexp-replaceregexp-substr
arunb2w
arunb2w

Reputation: 1196

Fetching value from Pipe-delimited String using Regex (Oracle)

I have a sample source string like below, which was in pipe delimited format in that the value obr can be at anywhere. I need to get the second value of the pipe from the first occurrence of obr. So for the below source strings the expected would be,

Source string:

select 'asd|dfg|obr|1|value1|end' text from dual
union all
select 'a|brx|123|obr|2|value2|end' from dual
union all
select 'hfv|obr|3|value3|345|pre|end' from dual

Expected output:

value1
value2
value3

I have tried the below regexp in oracle sql, but it is not working fine properly.

with t as (
            select 'asd|dfg|obr|1|value1|end' text from dual
            union all
            select 'a|brx|123|obr|2|value2|end' from dual
            union all
            select 'hfv|obr|3|value3|345|pre|end' from dual
            )
            select text,to_char(regexp_replace(text,'*obr\|([^|]*\|)([^|]*).*$', '\2')) output from t;

It is working fine when the string starts with OBR, but when OBR is in the middle like the above samples it is not working fine.

Any help would be appreciated.

Upvotes: 2

Views: 2759

Answers (2)

Gary_W
Gary_W

Reputation: 10360

This handles null elements and is wrapped in a NVL() call which supplies a value if 'obr' is not found or occurs too far toward the end of a record so a value 2 away is not possible:

SQL> with t(id, text) as (
     select 1, 'asd|dfg|obr|1|value1|end'      from dual
     union
     select 2, 'a|brx|123|obr|2|value2|end'    from dual
     union
     select 3, 'hfv|obr|3|value3|345|pre|end'  from dual
     union
     select 4, 'hfv|obr||value4|345|pre|end'   from dual
     union
     select 5, 'a|brx|123|obriem|2|value5|end' from dual
     union
     select 6, 'a|brx|123|obriem|2|value6|obr' from dual
   )
   select
     id,
     nvl(regexp_substr(text, '\|obr\|[^|]*\|([^|]*)(\||$)', 1, 1, null, 1), 'value not found') value
   from t;

        ID VALUE
---------- -----------------------------
         1 value1
         2 value2
         3 value3
         4 value4
         5 value not found
         6 value not found

6 rows selected.

SQL>

The regex basically can be read as "look for a pattern of a pipe, followed by 'obr', followed by a pipe, followed by zero or more characters that are not a pipe, followed by a pipe, followed by zero or more characters that are not a pipe (remembered in a captured group), followed by a pipe or the end of the line". The regexp_substr() call then returns the 1st captured group which is the set of characters between the pipes 2 fields from the 'obr'.

Upvotes: 0

Paurian
Paurian

Reputation: 1402

Not sure of how Oracle handles regular expressions, but starting with an asterisk usually implies that you're looking for zero or more null characters.

Have you tried '^.*obr\|([^|]*\|)([^|]*).*$' ?

Upvotes: 3

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