Impossible to match a digit with a REGEXP_REPLACE - sql

I try to extract the '930' from 'EM 930' with following Regexp
REGEXP_REPLACE(info,'^[:space:]*[ABCDEFGHIJKLMNOPQRSTUVWXYZ]*[:space:]*([0-9]+)[:space:]*$','\1')
But it returns me the original string.
An idea why ?
Subsidiary question:
Why does the "\1" returned the original string when the pattern is not matched ? I expected it to return NULL, as in my other regexp experiences (eg Perl).
Who I can re-write this in a performant way so that I get of wel the matched string of well NULL ?

Your space character class was not exactly correct. If we change [:space:] to [[:space:]], your regexp_replace works as you expect:
REGEXP_REPLACE(info, '^[[:space:]]*[ABCDEFGHIJKLMNOPQRSTUVWXYZ]*[[:space:]]*([0-9]+)[[:space:]]*$','\1')
For the sake of succinctness, we could use the upper character class, [[:upper:]], for [ABCDEFGHIJKLMNOPQRSTUVWXYZ]. This changes the function invocation to:
regexp_replace(info, '^[[:space:]]*[[:upper:]]*[[:space:]]*([0-9]+)[[:space:]]*$','\1')
Or escape characters could be used in lieu of character classes:
\s space
\w word character
\d digit character
regexp_replace(info, '^\s*\w*\s*(\d+)\s*$','\1')
Explanation:
Since your malformed character class, [:space:], does not match the space that exists between 'EM' and '930', your search by parameter does not match any characters in the source parameter.
Your search by parameter, '^[[:space:]]*[ABCDEFGHIJKLMNOPQRSTUVWXYZ]*[[:space:]]*([0-9]+)[[:space:]]*$', is anchored to the beginning and end of the column, info, thus it can only match the column, info, one time at most.
In your case, there is no match and the character group, '\1' which is associated with '([0-9]*)', has no value.
Consequently, no characters are replaced and you are left with original value of the column, info, 'EM 930'.
interesting variations to better understand this function:
-If your corrected function invocation had no pattern_to_replace_by parameter, '\1', then a NULL would be returned:
regexp_replace(info, '^\s*\w*\s*(\d+)\s*$' ) FROM dual;
-Since you have a pattern_to_replace_by parameter, '\1', and now it has the matching character group, the repeating digit group is returned:
930

Related

Replacing the nth white by an asterisk in GBQ

REGEXP_REPLACE("My dog is funny and happy", r"(\S+ \S+ \S+)", r"*") This is my SQL for achieving this. My output should look something like this = My dog is funny *and happy
When I try the above query it removes the first few words. How do I work this out?
You should use a backreference:
REGEXP_REPLACE("My dog is funny and happy", r"^((?:\S+\s+){4})", r"\1*")
REGEXP_REPLACE("My dog is funny and happy", r"^(?:\S+\s+){4}", r"\0*")
See the regex demo. Details:
^ - start of string
((?:\S+\s+){4}) - Group 1 (\1 in the replacement will refer to this group value): four occurrences of one or more non-whitespaces followed with one or more whitespaces.
\0 refers to the whole match value.
See the regexp_replace reference:
REGEXP_REPLACE(value, regexp, replacement)
Returns a STRING where all substrings of value that match regular
expression regexp are replaced with replacement.
You can use backslashed-escaped digits (\1 to \9) within the
replacement argument to insert text matching the corresponding
parenthesized group in the regexp pattern. Use \0 to refer to the
entire matching text.

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

Find phone numbers with unexpected characters using SQL in Oracle?

I need to find rows where the phone number field contains unexpected characters.
Most of the values in this field look like:
123456-7890
This is expected. However, we are also seeing character values in this field such as * and #.
I want to find all rows where these unexpected character values exist.
Expected:
Numbers are expected
Hyphen with numbers is expected (hyphen alone is not)
NULL is expected
Empty is expected
Tried this:
WHERE phone_num is not like ' %[0-9,-,' ' ]%
Still getting rows where phone has numbers.
from https://regexr.com/3c53v address you can edit regex to match your needs.
I am going to use example regex for this purpose
select * from Table1
Where NOT REGEXP_LIKE(PhoneNumberColumn, '^[+]*[(]{0,1}[0-9]{1,4}[)]{0,1}[-\s\./0-9]*$')
You can use translate()
...
WHERE translate(Phone_Number,'a1234567890-', 'a') is NOT NULL
This will strip out all valid characters leaving behind the invalid ones. If all the characters are valid, the result would be NULL. This does not validate the format, for that you'd need to use REGEXP_LIKE or something similar.
You can use regexp_like().
...
WHERE regexp_like(phone_num, '[^ 0123456789-]|^-|-$')
[^ 0123456789-] matches any character that is not a space nor a digit nor a hyphen. ^- matches a hyphen at the beginning and -$ on the end of the string. The pipes are "ors" i.e. a|b matches if pattern a matches of if pattern b matches.
Oracle has REGEXP_LIKE for regex compares:
WHERE REGEXP_LIKE(phone_num,'[^0-9''\-]')
If you're unfamiliar with regular expressions, there are plenty of good sites to help you build them. I like this one

How can I extract a substring from a character column without using SUBSTR()?

I have a questions regarding below data.
You clearly can see each EMP_IDENTIFIER has connected with EMP_ID.
So I need to pull only identifier which is 10 characters that will insert another column.
How would I do that?
I did some traditional way, using INSTR, SUBSTR.
I just want to know is there any other way to do it but not using INSTR, SUBSTR.
EMP_ID(VARCHAR2)EMP_IDENTIFIER(VARCHAR2)
62049 62049-2162400111
6394 6394-1368000222
64473 64473-1814702333
61598 61598-0876000444
57452 57452-0336503555
5842 5842-0000070666
75778 75778-0955501777
76021 76021-0546004888
76274 76274-0000454999
73910 73910-0574500122
I am using Oracle 11g.
If you want the second part of the identifier and it is always 10 characters:
select t.*, substr(emp_identifier, -10) as secondpart
from t;
Here is one way:
REGEXP_SUBSTR (EMP_IDENTIFIER, '-(.{10})',1,1,null,1)
That will give the 1st 10 character string that follows a dash ("-") in your string. Thanks to mathguy for the improvement.
Beyond that, you'll have to provide more details on the exact logic for picking out the identifier you want.
Since apparently this is for learning purposes... let's say the assignment was more complicated. Let's say you had a longer input string, and it had several groups separated by -, and the groups could include letters and digits. You know there are at least two groups that are "digits only" and you need to grab the second such "purely numeric" group. Then something like this will work (and there will not be an instr/substr solution):
select regexp_substr(input_str, '(-|^)(\d+)(-|$)', 1, 2, null, 2) from ....
This searches the input string for one or more digits ( \d means any digit, + means one or more occurrences) between a - or the beginning of the string (^ means beginning of the string; (a|b) means match a OR b) and a - or the end of the string ($ means end of the string). It starts searching at the first character (the second argument of the function is 1); it looks for the second occurrence (the argument 2); it doesn't do any special matching such as ignore case (the argument "null" to the function), and when the match is found, return the fragment of the match pattern included in the second set of parentheses (the last argument, 2, to the regexp function). The second fragment is the \d+ - the sequence of digits, without the leading and/or trailing dash -.
This solution will work in your example too, it's just overkill. It will find the right "digits-only" group in something like AS23302-ATX-20032-33900293-CWV20-3499-RA; it will return the second numeric group, 33900293.

Argument '0' is out of range error

I have a query (sql) to pull out a street name from a string. It's looking for the last occurrence of a digit, and then pulling the proceeding text as the street name. I keep getting the oracle
"argument '0' is out of range"
error but I'm struggling to figure out how to fix it.
the part of the query in question is
substr(address,regexp_instr(address,'[[:digit:]]',1,regexp_count(address,'[[:digit:]]'))+2)
any help would be amazing. (using sql developer)
The fourth parameter of regexp_instr is the occurrence:
occurrence is a positive integer indicating which occurrence of
pattern in source_string Oracle should search for. The default is 1,
meaning that Oracle searches for the first occurrence of pattern.
In this case, if an address has no digits within, the regexp_count will return 0, that's not a valid occurrence.
A simpler solution, which does not require separate treatment for addresses without a house number, is this:
with t (address) as (
select '422 Hickory Str.' from dual union all
select 'One US Bank Plaza' from dual
)
select regexp_substr(address, '\s*([^0-9]*)$', 1, 1, null, 1) as street from t;
The output looks like this:
STREET
-------------------------
Hickory Str.
One US Bank Plaza
The third argument to regexp_substr is the first of the three 1's. It means start the search at the first character of address. The second 1 means find the first occurrence of the search pattern. The null means no special match modifiers (such as case insensitive - nothing like that needed here). The last 1 means "return the first SUBEXPRESSION from the match pattern". Subexpressions are parts of the match expression enclosed in parentheses.
The match pattern has a $ at the end - meaning "anchor at the end of the input string" ($ means the end of the string). Then [...] means match any of the characters in square brackets, but the ^ in [^...] changes it to match any character OTHER THAN what is in the square brackets. 0-9 means all characters between 0 and 9; so [^0-9] means match any character(s) OTHER THAN digits, and the * after that means "any number of such characters" (between 0 and everything in the input string). \s is "blank space" - if there are any blank spaces following a possible number in the address, you don't want them included right at the beginning of the street name. The subexpression is just [^0-9]* meaning the non-digits, not including any spaces before them (because the \s* is outside the left parenthesis).
My example illustrates a potential problem though - sometimes an address does, in fact, have a "number" in it, but spelled out as a word instead of using digits. What I show is in fact a real-life address in my town.
Good luck!
looking for the last occurrence of a digit, and then pulling the proceeding text as the street name
You could simply do:
SELECT REGEXP_REPLACE( address, '^(.*)\d+\D*$', '\1' )
AS street_name
FROM address_table;