How to extract group from regular expression in Oracle? - sql

I got this query and want to extract the value between the brackets.
select de_desc, regexp_substr(de_desc, '\[(.+)\]', 1)
from DATABASE
where col_name like '[%]';
It however gives me the value with the brackets such as "[TEST]". I just want "TEST". How do I modify the query to get it?

The third parameter of the REGEXP_SUBSTR function indicates the position in the target string (de_desc in your example) where you want to start searching. Assuming a match is found in the given portion of the string, it doesn't affect what is returned.
In Oracle 11g, there is a sixth parameter to the function, that I think is what you are trying to use, which indicates the capture group that you want returned. An example of proper use would be:
SELECT regexp_substr('abc[def]ghi', '\[(.+)\]', 1,1,NULL,1) from dual;
Where the last parameter 1 indicate the number of the capture group you want returned. Here is a link to the documentation that describes the parameter.
10g does not appear to have this option, but in your case you can achieve the same result with:
select substr( match, 2, length(match)-2 ) from (
SELECT regexp_substr('abc[def]ghi', '\[(.+)\]') match FROM dual
);
since you know that a match will have exactly one excess character at the beginning and end. (Alternatively, you could use RTRIM and LTRIM to remove brackets from both ends of the result.)

You need to do a replace and use a regex pattern that matches the whole string.
select regexp_replace(de_desc, '.*\[(.+)\].*', '\1') from DATABASE;

Related

Extract characters in string following keyword and ending right before the other keyword

I have a table that looks like:
id
re|cid|13324242|
wa|cid|13435464|
fs|cid|2343532|
I want to extract information that is contained right after "|cid|" and before the following "|" element. That is:
13324242
13435464
2343532
I thought of substr() but there I don't know how to specify start and end element.
You could use REGEXP_REPLACE here (Standard SQL):
SELECT
id,
CASE WHEN id LIKE '%|cid|%'
THEN REGEXP_REPLACE(id, '^.*\|cid\|(\d+)\|.*$', '\1') END AS cid
FROM yourTable;
The idea is to use a regex replacement to extract the cid value from the id column, should it be present (and if not, we would just return NULL).
Here is a demo showing that the regex logic be correct.
If you want the third element (which appears to be the intention given the sample data), I would recommend split():
select (split(id, '|')[ordinal(3)]

How can I remove characters in a string after a specific special character (~) in snowflake sql?

I am using Snowflake SQL. I would like to remove characters from a string after a special character ~. How can I do that?
here is the whole scenario. Let me explain. I do have a string like 'CK#123456~fndkjfgdjkg'. Now, i want only the number after #.And not anything after ~. This is number length varies for that field value. It might be 1 or 5 or 3. And i want to add the condition in where class where this number is equal to check_num from other table after joining. I am trying REGEXP_SUBSTR(A.SRC_TXT, '(?<=CK#)(.+?\b)') = C.CHK_NUM in the where condition. I am getting the error as 'No repititive argument after ?'
You can use a regex for this
-- To remove just the character after a ~
select regexp_replace('fo~o bar','~.', '');
-- returns 'fo bar'
--If you want to keep the ~
select regexp_replace('fo~o bar','~.', '~');
-- returns 'fo~ bar'
--If you want to remove everything after the ~
select regexp_replace('fo~o bar','~.*', '');
--returns 'fo'
If you need to remove other specific character sets after a ~, you can probably do this with a slightly more complicated regex, but I'd need examples of your desired input/output to help with that.
EDIT for updated question
This regex replace should get what you need.
select regexp_replace('CK#123456~fndkjfgdjkg','CK#(\\d*)~.*', '\\1');
-- returns 123456
(\\d*) gets ANY number of digits in a row, and the \\1 causes it to replace the match with what was in the first set of parenthesis, which is your list of digits. the CK# and ~.* are there to make sure the whole string gets matched and replaced.
If the CK# can vary as well, you can use .*? like this.
select regexp_replace('ABCD123HI#123456~fndkjfgdjkg','.*?#(\\d*)~.*', '\\1')
-- returns 123456
I'd probably do something like the following, easy enough but not as cool as RegEx type of functions.
set my_string='fooo~12345';
set search_for_me = '~';
SELECT SUBSTR($my_string, 1, DECODE(position($search_for_me, $my_string), 0, length($my_string), position($search_for_me, $my_string)));
I hope this helps...Rich
It looks like lookahead and lookbehinds are not supported in REGEXP functions, they seem to work in the PATTERN clause of a LIST command. Snowflake documentation makes no mention either way of lookahead or lookbehinds.
In your example:
It seems that the query engine is looking for that repeating argument, where you are attempting a lookbehind
You have not specified what you wanted extracted. You have two capture groups, but in this scenario everything would be returned
Since you are looking to remove everything after ~ you have a delimiter, why not use it in your REGEXP_SUBSTR function?
Try the following:
SELECT $1,REGEXP_SUBSTR($1,'\\w+#(.+?)~',1,1,'is',1)
FROM VALUES
('CK#123456~fndkjfgdjkg')
,('QH#128fklj924~fndkjfgdjkg')
;
This looks for:
One or more word characters
Followed by #
Capturing one or more characters upto and not including ~
Returns the characters within the capture group
You can change the .+? to \\d+? to make sure the pattern is only digits. Backslashes must be escaped with a backslash.
The descriptions for each argument of the function can be found here:
https://docs.snowflake.net/manuals/sql-reference/functions/regexp_substr.html
You could check this!!
select substr('CK#123456~fndkjfgdjkg',4,6) from dual;
OUTPUT
123456
https://docs.snowflake.net/manuals/sql-reference/functions/substr.html

Use REGEXP_SUBSTR to extract string of varied length

I want to extract alphanumeric text of varied length from a string between the second occurrence of a specific characters.
I have tried various forms of substr and regexp_substr but can't seem to get the syntax right. This is for use in Teradata SQL assistant. In the past I would have to create a temp table and use substr twice before trimming down the string to what I need. I want to do it all in one go.
SELECT regexp_substr('Channel:DF GB, Order Num:12345T6, Order Date:01/01/2019, Charge Codes:TAXES,,GBRAX', 'Num\\:+(\\:+)',1,2, ':') as RESULTING_STRING
My desired result is to return ONLY what is between "Num:" and the next "," in this case "12345T6". The length of the order number can vary so it is not a fixed length. When I run my code the actual output is a '?' returned by Teradata. What am I doing wrong?
This seems to work:
SELECT regexp_substr('Channel:DF GB, Order Num:12345T6, Order Date:01/01/2019, Charge Codes:TAXES,,GBRAX', 'Num:(\w*)', 1, 1, NULL, 1) as RESULTING_STRING from dual
Finds Num: and then captures as many word characters (, is not a word char) as there are available. The last parameter - subexpr - specifies which subexpression (aka capture group) you want, without it the whole thing will be matched (Num:12345T6).
Assuming you use Teradata SQL Assistant to query a Teradata system (but why do you tag Oracle then) the RegEx syntax is slightly different (both use a different RegEx dialects):
Teradata's RegExp_Substr doesn't support the subexpression parameter, you can either switch to the (I really don't know why) undocumented RegExp_Substr_gpl
RegExp_Substr_gpl(x, 'Num:([^,]*)', 1, 1, 'i', 1)
or tell the RegEx to forget the previous match using \K:
RegExp_Substr(x, 'Num:\K[^,]*', 1,1, 'i')
You can give a try to the below pattern search !
SELECT REGEXP_REPLACE ((REGEXP_SUBSTR('Channel:DF GB, Order Num:12345T6, Order Date:01/01/2019, Charge Codes:TAXES,,GBRAX', 'Num:[A-Za-z0-9]*',1,1, 'i')),'Num:','',1,1,'i') AS RESULTING_STRING
Regexp_substr pattern search ['Num:[A-Za-z0-9]*'], will first filter out the alphanumeric characters that follow the pattern 'Num:',astriek, helps to find out zero or more occurrences of the specified pattern.
For eg:, in this 'Num:12345T6' will be filtered out of the string provided, also note the last parameter in the regexp_substr is 'i', which ensures case in-specific search.
Lastly, Regexp_replace will replace the pattern 'Num:' from the output of the regexp_substr with an empty string,resulting in a final string as '12345T6'.

Extract a number from comma separated string using regular expressions in oracle sql

I am trying to fetch a number which starts with 628 in a comma separated string.
Below is what I am using:
SELECT
REGEXP_REPLACE(REGEXP_SUBSTR('62810,5152,,', ',?628[[:alnum:]]+,?'),',','') first,
REGEXP_REPLACE(REGEXP_SUBSTR('5152,62810,,', ',?628[[:alnum:]]+,?'),',','') second,
REGEXP_REPLACE(REGEXP_SUBSTR('5152,562810,,', ',?628[[:alnum:]]+,?'),',','') third,
REGEXP_REPLACE(REGEXP_SUBSTR(',5152,,62810', ',?(628[[:alnum:]]+),?'),',','') fourth
FROM DUAL;
Its working but in one case it fails which is the third column where number is 562810. Actually I am expecting NULL in the third column.
Actual output from above query is:
"FIRST","SECOND","THIRD","FOURTH"
"62810","62810","62810","62810"
Not sure why you are using [[:alnum::]]. You could use matching group to extract the number starting with 628 or followed by a comma. REPLACE may be avoided this way
If you have alphabets as well, modify the 2nd match group () accordingly.
SELECT
REGEXP_SUBSTR('62810,5152,,' , '(^|,)(628\d*)',1,1,NULL,2) first,
REGEXP_SUBSTR('5152,62810,,' , '(^|,)(628\d*)',1,1,NULL,2) second,
REGEXP_SUBSTR('5152,562810,,', '(^|,)(628\d*)',1,1,NULL,2) third,
REGEXP_SUBSTR(',5152,,62810' , '(^|,)(628\d*)',1,1,NULL,2) fourth
FROM DUAL;
Demo
The problem with your regex logic is that you are searching for an optional comma before the numbers 628. This means that any number having 628 anywhere would match. Instead, you can phrase this by looking for 628 which is either preceded by either a comma, or the start of the string.
SELECT
REGEXP_REPLACE(REGEXP_SUBSTR('62810,5152,,', '(,|^)628[[:alnum:]]+,?'),',','') first,
REGEXP_REPLACE(REGEXP_SUBSTR('5152,62810,,', '(,|^)628[[:alnum:]]+,?'),',','') second,
REGEXP_REPLACE(REGEXP_SUBSTR('5152,562810,,', '(,|^)628[[:alnum:]]+,?'),',','') third,
REGEXP_REPLACE(REGEXP_SUBSTR(',5152,,62810', '(,|^)(628[[:alnum:]]+),?'),',','') fourth
FROM DUAL
Demo
The ideal pattern we'd like to use here is \b628.*, or something along these lines. But Oracle's regex functions do not appear to support word boundaries, hence we can use (^|,)628.* as an alternative.

replace all occurrences of a sub string between 2 charcters using sql

Input string: ["1189-13627273","89-13706681","118-13708388"]
Expected Output: ["14013627273","14013706681","14013708388"]
What I am trying to achieve is to replace any numbers till the '-' for each item with hard coded text like '140'
SELECT replace(value_to_replace, '-', '140')
FROM (
VALUES ('1189-13627273-77'), ('89-13706681'), ('118-13708388')
) t(value_to_replace);
check this
I found the right way to achieve that using the below regular expression.
SELECT REGEXP_REPLACE (string_to_change, '\\"[0-9]+\\-', '140')
You don't need a regexp for this, it's as easy as concatenation of 140 and the substring from - (or the second part when you split by -)
select '140'||substring('89-13706681' from position('-' in '89-13706681')+1 for 1000)
select '140'||split_part('89-13706681','-',2)
also, it's important to consider if you might have instances that don't contain - and what would be the output in this case
Use regexp_replace(text,text,text) function to do so giving the pattern to match and replacement string.
First argument is the value to be replaced, second is the POSIX regular expression and third is a replacement text.
Example
SELECT regexp_replace('1189-13627273', '.*-', '140');
Output: 14013627273
Sample data set query
SELECT regexp_replace(value_to_replace, '.*-', '140')
FROM (
VALUES ('1189-13627273'), ('89-13706681'), ('118-13708388')
) t(value_to_replace);
Caution! Pattern .*- will replace every character until it finds last occurence of - with text 140.