SQL Server Regular Expression Workaround in T-SQL? - regex

I have some SQLCLR code for working with Regular Expresions. But now that it is getting migrated into Azure, which does not allow SQLCLR, that's out. I need to find a way to do regex in pure T-SQL.
Master Data Services are not available because the dev edition of MSSQL we have is not R2.
All ideas appreciated, thanks.
Regular expression match samples that need handling
(culled from regexlib and other places over the past few years)
email address
^[\w-]+(\.[\w-]+)*#([a-z0-9-]+(\.[a-z0-9-]+)*?\.[a-z]{2,6}|(\d{1,3}\.){3}\d{1,3})(:\d{4})?$
dollars
^(\$)?(([1-9]\d{0,2}(\,\d{3})*)|([1-9]\d*)|(0))(\.\d{2})?$
uri
^(http|https|ftp)\://([a-zA-Z0-9\.\-]+(\:[a-zA-Z0-9\.&%\$\-]+)*#)*((25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9])\.(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9]|0)\.(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9]|0)\.(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[0-9])|localhost|([a-zA-Z0-9\-]+\.)*[a-zA-Z0-9\-]+\.(com|edu|gov|int|mil|net|org|biz|arpa|info|name|pro|aero|coop|museum|[a-zA-Z]{2}))(\:[0-9]+)*(/($|[a-zA-Z0-9\.\,\?\'\\\+&%\$#\=~_\-]+))*$
one numeric digit
^\d$
percentage
^-?[0-9]{0,2}(\.[0-9]{1,2})?$|^-?(100)(\.[0]{1,2})?$
height notation
^\d?\d'(\d|1[01])"$
numbers between 1 1000
^([1-9]|[1-9]\d|1000)$
credit card numbers
^((4\d{3})|(5[1-5]\d{2})|(6011))-?\d{4}-?\d{4}-?\d{4}|3[4,7]\d{13}$
list of years
^([1-9]{1}[0-9]{3}[,]?)*([1-9]{1}[0-9]{3})$
days of the week
^(Sun|Mon|(T(ues|hurs))|Fri)(day|\.)?$|Wed(\.|nesday)?$|Sat(\.|urday)?$|T((ue?)|(hu?r?))\.?$
time on 12 hour clock
(?<Time>^(?:0?[1-9]:[0-5]|1(?=[012])\d:[0-5])\d(?:[ap]m)?)
time on 24 hour clock
^(?:(?:(?:0?[13578]|1[02])(\/|-|\.)31)\1|(?:(?:0?[13-9]|1[0-2])(\/|-|\.)(?:29|30)\2))(?:(?:1[6-9]|[2-9]\d)?\d{2})$|^(?:0?2(\/|-|\.)29\3(?:(?:(?:1[6-9]|[2-9]\d)?(?:0[48]|[2468][048]|[13579][26])|(?:(?:16|[2468][048]|[3579][26])00))))$|^(?:(?:0?[1-9])|(?:1[0-2]))(\/|-|\.)(?:0?[1-9]|1\d|2[0-8])\4(?:(?:1[6-9]|[2-9]\d)?\d{2})$
usa phone numbers
^\(?[\d]{3}\)?[\s-]?[\d]{3}[\s-]?[\d]{4}$

Unfortunately, you will not be able to move your CLR function(s) to SQL Azure. You will need to either use the normal string functions (PATINDEX, CHARINDEX, LIKE, and so on) or perform these operations outside of the database.
EDIT Adding some information for the examples added to the question.
Email address
This one is always controversial because people disagree about which version of the RFC they want to support. The original didn't support apostrophes, for example (or at least people insist that it didn't - I haven't dug it up from the archives and read it myself, admittedly), and it has to be expanded quite often for new TLDs (once for 4-letter TLDs like .info, then again for 6-letter TLDs like .museum). I've often heard quite knowledgeable people state that perfect e-mail validation is impossible, and having previously worked for an e-mail service provider, I can tell you that it was a constantly moving target. But for the simplest approaches, see the question TSQL Email Validation (without regex).
One numeric digit
Probably the easiest one of the bunch:
WHERE #s LIKE '[0-9]';
Credit card numbers
Assuming you strip out dashes and spaces, which you should do in any case. Note that this isn't an actual check of the credit card number algorithm to ensure that the number itself is actually valid, just that it conforms to the general format (AmEx = 15 digits starting with a 3, the rest are 16 digits - Visa starts with a 4, MasterCard starts with a 5, Discover starts with 6 and I think there's one that starts with a 7 (though that may just be gift cards of some kind)):
WHERE #s + ' ' LIKE '[3-7]'+ REPLICATE('[0-9]', 14) + '[0-9 ]';
If you want to be a little more precise at the cost of being long-winded, you can say:
WHERE (LEN(#s) = 15 AND #s LIKE '3' + REPLICATE('[0-9]', 14))
OR (LEN(#s) = 16 AND #s LIKE '[4-7]' + REPLICATE('[0-9]', 15));
USA phone numbers
Again, assuming you're going to strip out parentheses, dashes and spaces first. Pretty sure a US area code can't start with a 1; if there are other rules, I am not aware of them.
WHERE #s LIKE '[2-9]' + REPLICATE('[0-9]', 9);
-----
I'm not going to go further, because a lot of the other expressions you've defined can be extrapolated from the above. Hopefully this gives you a start. You should be able to Google for some of the others to see how other people have replicated the patterns with T-SQL. Some of them (like days of the week) can probably just be checked against a table - seems overkill to do an invasie pattern matching for a set of 7 possible values. Similarly with a list of 1000 numbers or years, these are things that will be much easier (and probably more efficient) to check if the numeric value is in a table rather than convert it to a string and see if it matches some pattern.
I'll state again that a lot of this will be much better if you can cleanse and validate the data before it gets into the database in the first place. You should strive to do this wherever possible, because without CLR, you just can't do powerful RegEx inside SQL Server.

Ken Henderson wrote about ways to replicate RegEx without CLR, but they require sp_OA* procedures, which are even less likely to ever see the light of day in Azure than CLR. Most of the other articles you'll find online use an approach similar to Ken's or use complex use of built-in string functions.
Which portions of RegEx specifically are you trying to replicate? Can you show an example of the input/output of one of your functions? Perhaps it will be easy to convert to get similar results using the built-in string functions like PATINDEX.

Related

Regex - How can you identify strings which are not words?

Got an interesting one, and can't come up with any solid ideas, so thought maybe someone else may have done something similar.
I want to be able to identify strings of letters in a longer sentence that are not words and remove them. Essentially things like kuashdixbkjshakd
Everything annoyingly is in lowercase which makes it more difficult, but since I only care about English, I'm essentially looking for the opposite of consonant clusters, groups of them that don't make phonetically pronounceable sounds.
Has anyone heard of/done something like this before?
EDIT: this is what ChatGpt tells me
It is difficult to provide a comprehensive list of combinations of consonants that have never appeared in a word in the English language. The English language is a dynamic and evolving language, and new words are being created all the time. Additionally, there are many regional and dialectal variations of the language, which can result in different sets of words being used in different parts of the world.
It is also worth noting that the frequency of use of a particular combination of consonants in the English language is difficult to quantify, as the existing literature on the subject is limited. The best way to determine the frequency of use of a particular combination of consonants would be to analyze a large corpus of written or spoken English.
In general, most combinations of consonants are used in some words in the English language, but some combinations of consonants may be relatively rare. Some examples of relatively rare combinations of consonants in English include "xh", "xw", "ckq", and "cqu". However, it is still possible that some words with these combinations of consonants exist.
You could try to pass every single word inside the sentence to a function that checks wether the word is listed inside a dictionary. There is a good number of dictionary text files on GitHub. To speed up the process: use a hash map :)
You could also use an auto-corretion API or a library.
Algorithm to combine both methods:
Run sentence through auto correction
Run every word through dictionary
Delete words that aren't listed in the dictionary
This could remove typos and words that are non-existent.
You could train a simple model on sequences of characters which are permitted in the language(s) you want to support, and then flag any which contain sequences which are not in the training data.
The LangId language detector in SpamAssassin implements the Cavnar & Trenkle language-identification algorithm which basically uses a sliding window over the text and examines the adjacent 1 to 5 characters at each position. So from the training data "abracadabra" you would get
a 5
ab 2
abr 2
abra 2
abrac 1
b 2
br 2
bra 2
brac 1
braca 1
:
With enough data, you could build a model which identifies unusual patterns (my suggestion would be to try a window size of 3 or smaller for a start, and train it on several human languages from, say, Wikipedia) but it's hard to predict how precise exactly this will be.
SpamAssassin is written in Perl and it should not be hard to extract the language identification module.
As an alternative, there is a library called libtextcat which you can run standalone from C code if you like. The language identification in LibreOffice uses a fork which they adapted to use Unicode specifically, I believe (though it's been a while since I last looked at that).
Following Cavnar & Trenkle, all of these truncate the collected data to a few hundred patterns; you would probably want to extend this to cover up to all the 3-grams you find in your training data at least.
Perhaps see also Gertjan van Noord's link collection: https://www.let.rug.nl/vannoord/TextCat/
Depending on your test data, you could still get false positives e.g. on peculiar Internet domain names and long abbreviations. Tweak the limits for what you want to flag - I would think that GmbH should be okay even if you didn't train on German, but something like 7 or more letters long should probably be flagged and manually inspected.
This will match words with more than 5 consonants (you probably want "y" to not be considered a consonant, but it's up to you):
\b[a-z]*[b-z&&[^aeiouy]]{6}[a-z]*\b
See live demo.
5 was chosen because I believe witchcraft has the longest chain of consonants of any English word. You could dial back "6" in the regex to say 5 or even 4 if you don't mind matching some outliers.

Regex masking all phone numbers except a specific range

Not 100% if this is possible but I would like to convert any outbound call that does not match my DID range to a set phone number. 
With our carrier in Australia if the ANI is not from their supplied range the call is blocked as part of new regulations. 
What I am looking for is something like this. 
if not +61 2 XXXX XXXX - +61 2 XXXX  XXXX  then send as +612XXXX XXXX
I apologise I have no true understanding of regex and do not know even where to begin.
I am starting to work on my knowledge of it though. please be kind. If anyone can point me to an "idiots guide" link I would be appreciative as I am just getting into this.
Of course it's possible. It's just a matter of how much work you want to do. I'm not quite sure what you want to mask and what you want to pass on unmutilated. A couple of particular examples would help. How many different formats, countries, and so on do you need to support?
With these problems, I tend to follow this approach:
Normalize the data. Make them all look the same. So, remove all non-digits, for example. +61 2 XXXX XXXX turns into 612XXXXXXXX. In this step, you'd also fill in implicit information, like a local number that does not include the country code. Number::Phone may be interesting, but, also note is was the largest distro on CPAN for awhile.
Now it should be easier to recognize the number and it's components (because if it isn't, you didn't do Step 1 right). Instead of a regex, you might use a parser. That is, get the country code, and then from that, decide what has to happen next. That's the sort of thing I have to do with ISBNs in Business::ISBN, which have a group code then a publisher code (both of which are variable length.
Once you can recognize the number, it's easy to select a range. If it's in the range, you know what to replace.

Validate Street Address Format

I'm trying to validate the format of a street address in Google Forms using regex. I won't be able to confirm it's a real address, but I would like to at least validate that the string is:
[numbers(max 6 digits)] [word(minimum one to max 8 words with
spaces in between and numbers and # allowed)], [words(minimum one to max four words, only letters)], [2
capital letters] [5 digit number]
I want the spaces and commas I left in between the brackets to be required, exactly where I put them in the above example. This would validate
123 test st, test city, TT 12345
That's obviously not a real address, but at least it requires the entry of the correct format. The data is coming from people answering a question on a form, so it will always be just an address, no names. Plus they're all address is one area South Florida, where pretty much all addresses will match this format. The problem I'm having is people not entering a city, or commas, so I want to give them an error if they don't. So far, I've found this
^([0-9a-zA-Z]+)(,\s*[0-9a-zA-Z]+)*$
But that doesn't allow for multiple words between the commas, or the capital letters and numbers for zip. Any help would save me a lot of headaches, and I would greatly appreciate it.
There really is a lot to consider when dealing with a street address--more than you can meaningfully deal with using a regular expression. Besides, if a human being is at a keyboard, there's always a high likelihood of typing mistakes, and there just isn't a regex that can account for all possible human errors.
Also, depending on what you intend to do with the address once you receive it, there's all sorts of helpful information you might need that you wouldn't get just from splitting the rough address components with a regex.
As a software developer at SmartyStreets (disclosure), I've learned that regular expressions really are the wrong tool for this job because addresses aren't as 'regular' (standardized) as you might think. There are more rigorous validation tools available, even plugins you can install on your web form to validate the address as it is typed, and which return a wealth of of useful metadata and information.
Try Regex:
\d{1,6}\s(?:[A-Za-z0-9#]+\s){0,7}(?:[A-Za-z0-9#]+,)\s*(?:[A-Za-z]+\s){0,3}(?:[A-Za-z]+,)\s*[A-Z]{2}\s*\d{5}
See Demo
Accepts Apt# also:
(^[0-9]{1,5}\s)([A-Za-z]{1,}(\#\s|\s\#|\s\#\s|\s)){1,5}([A-Za-z]{1,}\,|[0-9]{1,}\,)(\s[a-zA-Z]{1,}\,|[a-zA-Z]{1,}\,)(\s[a-zA-Z]{2}\s|[a-zA-Z]{2}\s)([0-9]{5})

Regex improvements for international, common and RF3966 phone number validation?

Context
Hi, earlier I was browsing the web in order to find a quick answer about telephone number validation in one regex formula : for emergency, short, international, french, spanish and north american numbers (normal, fancy and extended versions).
Strangely, I couldn't find better than "A comprehensive regex for phone number formula", since it seems to be the best topic about this, or I missed it, which is totally possible.
So I'm new to the site and actually writing this very first question (yeah!), since that other thread is currently on hold of some sort : seems the author didn't get what he and I were seeking.
That makes at least three of us who would like to have a good solution, as I know at least my pal, the one who asked me first about finding one to be used in simple integrations like his Google Forms.
Hence my current question(s) and own answer to begin with, since I took some night time to build my own based on advices and tests patterns from the best replies on the other thread. If you're interested by the topic, there are some interesting elements.
Questions
What is the best way to optimize and improve this regex (without resorting to coding) which is dedicated to validation of international and most national phone numbers (along the recommendations of RFC 3966 at least)?
Not sure if I can add a related question as well (since it is still on purpose to improve the usefulness of the regex pattern), no harm asking I guess.
Are there other commonly-used formats that this regex should match (and not)?
If you can add them (or a link) here for me to update my test bundles, I would be thankful. Equally useful would be phone numbers that should definitely not be validated (the unwanted).
My initial solution
My current regex solution (version 4) on Regular Expressions 101
An earlier version was matching results despite leading and trailing whitespaces, not that useful to the point (a bit too fancy for the exceution time).
The latest version at the time of writing took into consideration the other posts on the subject RFC 3966 (from the IETF standards) and the wikipedia article on "Natural conventions for writing telephone numbers".
Another potentially side dish is to isolate matching groups for country code, area code and extended code... and things work relatively dandy to a certain point : it only works well when there are some separators (or the parenthesis) to distinguish those groups of digits.
Matching goals
Emergency and short numbers : 112 or 911
Spanish international : +34 987 654 321
French extended +33 (0)1 23 45 67 89
French national : 01 23 45 67 89
American extended : 001-(123)-456-7890 ext-4321
German (Microsoft style) : +49 (1234) 567890
Mexican national : (01 55) 1234 5678
Hypothetical international number (max length?) : 00321-(4321)-567.89 ext-4321
Another matching goal is to have a regex that do not under-perform too much, not really picky since it is not to be used in critical parts of code.
Still, how could we optimize those best regex(es) people will find/propose without changing their results?
Goals from the main thread
+1(234)/567.8901 x1234 and the like (with different permutations of separators : ., /, - and horizontal whitespaces.
2345678901 : same US number dialed in the states I guess.
Not sure how it should work since I though that + (or its equivalent the double zero 00) was required in front of any international number... always done it that way. The other thread had a list of positive matches without.
Could someone confirm that + or 00 is not mandatory to US numbers? Thank you again.
Best of unwanted formats
12(34567890 and 123)456789012345 : unmatched parenthesis.
)123(34567890 : parenthesis are wrongly matched.
++34123456789 : double + is a typo.
+9-123/456.7890 x12345 : ext has 4 numbers top.
1-234-567-8901 : missing 00 or + at the beginning of an international number.
1234 to 12345678 : not a short number, yet not a normal one (between 9 and 12? as far as i know).
1234567890123 : over max length (since without international features).
0012312345678901 : over max length (as international number).
Regex101.com was a big plus to rewrite and test the regex to this point, I couldn't have progressed so far without its help. Yet, I'm no expert so I can only scratch the surface here and I need your help to improve this.
Thank you for reading, it was very educating to write the question (but not something I would do every day, very time-consuming at my pace), hope it will find its answers as well. Have a nice day (or night... ;) ).
Before I forgot, here's the post of the latest version of the regex I put together and its code :
^(?=(?:\+|0{2})?(?:(?:[\(\-\)\.\/ \t\f]*\d){7,10})?(?:[\-\.\/ \t\f]?\d{2,3})(?:[\-\s]?[ext]{1,3}[\-\.\/ \t\f]?\d{1,4})?$)((?:\+|0{2})\d{0,3})?(?:[\-\.\/ \t\f]?)(\(0\d[ ]?\d{0,4}\)|\(\d{0,4}\)|\d{0,4})(?:[\-\.\/ \t\f]{0,2}\d){3,8}(?:[\-\s]?(?:x|ext)[\-\t\f ]?(\d{1,4}))?$
As far as I know, it pass the tests I put in the question and some more that I added on that Regex101.com page. You can even fork it, very useful feature indeed, I'm a new fan. :)
The code seems to work, as is, with PHP (pcre), Python and Javascript (but not Golang) with different performance that are not awesome but good enough for our purpose.
For instance, I wanted to use \h for horizontal whitespaces (instead of \t, \f and space, but it is less compatible with the different platforms.
It still need a lot of improvements, and I'm eager to see what you will be cooking to answer this little problem of ours, but I'm spent... already a sunny morning here. Good night folks.

Excluding % from a Regex number search

I'm attempting to create a Regex that finds only 2-digit integers or numbers with a precision of 2 decimal points.
In the example string at the bottom, I want to find only the following:
21 and 10.50
Using this expression, 100% is getting captured, in addition to the strings I desire to capture:
(\d){1,2}(\.?)([0-9]?[0-9]?){1,2}
I know I need to use ^% somewhere, but I can't figure out where it goes. Any suggestions are greatly appreciated.
Here's my sample string:
Earn Up to $21 Per Hour - Deliver Food with !!
Delivery Drivers work when they want and make great money when they do.
All orders are prepaid, just pick them up and deliver them to hungry diners. No waiting in line or fumbling with receipts and prepaid cards.
It's fast and easy to start working. Get started today.
Apply Now
Why choose ?
More orders than any other takeout platform
100% of our restaurants are official partners
Competitive pay: Per order fee + mileage + tips
We guarantee an hourly minimum of $10.50/hour*
Create your own schedule & work the hours you want
Word boundaries in your regular expression will grant you a bit more control.
Since word boundaries are a bit strict, we need to introduce an OR condition to address both cases which will satisfy your regex.
(\b[\d]{2}\.[\d]{2}\b)|(\b[\d]{2}\b)
Edit: Try this one,
\b[\d]{2}\b(\.[\d]{2})?
The first example has a chance to fail as it is order dependent due to the way it short-circuits. This I believe should address multiple cases properly.
I think this should work:
(?<!\d)((\d+\.\d\d)|(\d\d))(?!%|\d)
Demo (and explanation)
EDIT:
Improved version:
(?<!\d)(\d{1,2}(?:\.\d{1,2})?)(?!%|\d)
Demo (and explanation)
You can try this variant: (\d{1,}|[\d.])\b(?!%)
It uses negative lookahead (?!%) to exclude digits following by % sign.
Details at regex101