Extract first numeric value from a string

Question

Extract first numeric value from a string

valeryk2000

SSCarpal Tunnel

Points: 4245
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June 27, 2013 at 12:57 pm

#295742

Brothers,
I need to parse the first numeric value from a string that usually contains several numerics.
This function works OK when the first number has no decimals ( 1 - returns '500000').
In #2 (naturally!) the result is 0
Can you spare some help?
alter FUNCTION dbo.fnExtractDigits (@inString VARCHAR(8000))
RETURNS VARCHAR(8000) AS
BEGIN
DECLARE @X VARCHAR(100)
Select @X=@inString
Select @X= SubString(@X,PATINDEX('%[0-9]%',@X),Len(@X))
Select @X= SubString(@X,0,PATINDEX('%[^0-9]%',@X))
RETURN @X
END
-- 1. select dbo.fnExtractDigits ('NYSTATIN SUSP 500000 UNIT = 5 ML (1 5 ML CUP)')
-- 2. select dbo.fnExtractDigits ('NYSTATIN SUSP 0.75 UNIT = 5 ML (1 5 ML CUP)')

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Sean Lange SSC Guru Points: 286590 More actions · Answer 1

I would recommend NOT doing this as a scalar function. Scalar functions are not good for performance. You can easily leverage the DelimitedSplit8K function for this.

select top 1 *

from dbo.DelimitedSplit8K('NYSTATIN SUSP 500000 UNIT = 5 ML (1 5 ML CUP)', ' ')

where Item not like '%[^0-9.]%'

select top 1 *

from dbo.DelimitedSplit8K('NYSTATIN SUSP 0.75 UNIT = 5 ML (1 5 ML CUP)', ' ')

where Item not like '%[^0-9.]%'

You can find the code the that function by following the link in my signature about splitting strings.

_______________________________________________________________

Need help? Help us help you.

Read the article at http://www.sqlservercentral.com/articles/Best+Practices/61537/ for best practices on asking questions.

Need to split a string? Try Jeff Modens splitter http://www.sqlservercentral.com/articles/Tally+Table/72993/.

Cross Tabs and Pivots, Part 1 – Converting Rows to Columns - http://www.sqlservercentral.com/articles/T-SQL/63681/
Cross Tabs and Pivots, Part 2 - Dynamic Cross Tabs - http://www.sqlservercentral.com/articles/Crosstab/65048/
Understanding and Using APPLY (Part 1) - http://www.sqlservercentral.com/articles/APPLY/69953/
Understanding and Using APPLY (Part 2) - http://www.sqlservercentral.com/articles/APPLY/69954/

David Webb-CDS SSCoach Points: 17398 More actions · Answer 2

Sis,

Provided you don't have '.' anywhere except as a decimal separator:

alter FUNCTION dbo.fnExtractDigits (@inString VARCHAR(8000))

RETURNS VARCHAR(8000) AS

BEGIN

DECLARE @X VARCHAR(100)

Select @X=@inString

Select @X= SubString(@X,PATINDEX('%[0-9]%',@X),Len(@X))

Select @X= SubString(@X,0,PATINDEX('%[^.0-9]%',@X))

RETURN @X

END

And then again, I might be wrong ...
David Webb

valeryk2000 SSCarpal Tunnel Points: 4245 More actions · Answer 3

valeryk2000

SSCarpal Tunnel

Points: 4245

June 27, 2013 at 1:32 pm

#1628105

Thanks Sean. Will read (love charts!)

Sean Lange SSC Guru Points: 286590 More actions · Answer 4

Let's take the excellent example from David and turn it into a iTVF instead of a scalar function.

create FUNCTION dbo.fnExtractDigits (@inString VARCHAR(8000))

RETURNS table

return

select SubString(

SubString(@inString, PATINDEX('%[0-9]%', @inString), Len(@inString)), 0,

PATINDEX('%[^.0-9]%', SubString(@inString,PATINDEX('%[0-9]%',@inString),Len(@inString)))) as MyValue

Now we can really leverage some power and performance.

--need to setup our test data

;with myCte(SomeKey, SomeValue) as

(

select 1, 'NYSTATIN SUSP 500000 UNIT = 5 ML (1 5 ML CUP)' union all

select 2, 'NYSTATIN SUSP 0.75 UNIT = 5 ML (1 5 ML CUP)'

)

--now we can retrieve it

select *

from myCte

cross apply dbo.fnExtractDigits(SomeValue) s

_______________________________________________________________

Need help? Help us help you.

Read the article at http://www.sqlservercentral.com/articles/Best+Practices/61537/ for best practices on asking questions.

Need to split a string? Try Jeff Modens splitter http://www.sqlservercentral.com/articles/Tally+Table/72993/.

Cross Tabs and Pivots, Part 1 – Converting Rows to Columns - http://www.sqlservercentral.com/articles/T-SQL/63681/
Cross Tabs and Pivots, Part 2 - Dynamic Cross Tabs - http://www.sqlservercentral.com/articles/Crosstab/65048/
Understanding and Using APPLY (Part 1) - http://www.sqlservercentral.com/articles/APPLY/69953/
Understanding and Using APPLY (Part 2) - http://www.sqlservercentral.com/articles/APPLY/69954/

valeryk2000 SSCarpal Tunnel Points: 4245 More actions · Answer 5

Dave - thanks, it works -need to play to make sure it's ok in other strings

Thanks

(I can only be your brother, not sister - need to ask dad 😉

David Webb-CDS SSCoach Points: 17398 More actions · Answer 6

Sean has the best idea. His implementation will be far better behaved than the code I posted.

And then again, I might be wrong ...
David Webb

valeryk2000 SSCarpal Tunnel Points: 4245 More actions · Answer 7

Ha! Sean, you elegantly rewrote my function (stollen from somwhere anyway).

I do not think that to use cte in my case is a good idea - I use this function within a select statement from a big table - not sure that cte can be used here

SELECT

Real_Date_Time ChartedAt

,DRUG_INFO_1

,LEFT(drug_info_1,CHARINDEX(CHAR(32),drug_info_1)) Drug

,dbo.fnExtractDigits(DRUG_INFO_1) as DoseOrFirstNumeric

, Coalesce(case charindex('MG', DRUG_INFO_1)

when 0 then null

else 'MG'

end --Mg

,case charindex('GM', DRUG_INFO_1)

when 0 then null

else 'GM'

end --GM

,case charindex('UNIT', DRUG_INFO_1)

when 0 then null

else 'UNITS'

end ----UNITS

)

,ROUTE

,NO_OF_INGREDIENTS

,PMP

,pat_num

,ADMIN_STATUS

FROM MAK_Data.dbo.CHRT_Tran

Where

LEFT(drug_info_1,CHARINDEX(CHAR(32),drug_info_1))

IN

(

'abacavir', 'acyclovir', 'amikacin', 'amoxicillin', 'amoxicillin-clavulanic', 'amphotericin', 'ampicillin',

'ampicillin-sulbactam', 'atazanavir', 'atovaquone', 'azithromycin', 'aztreonam',

'cefazolin', 'cefdinir', 'cefepime', 'cefixime', 'cefotaxime', 'cefotetan',

'cefoxitin', 'cefpodoxime proxetil', 'ceftazidime', 'ceftriaxone', 'cefuroxime',

'cefuroxime axetil', 'cephalexin', 'ciprofloxacin', 'clarithromycin', 'clindamycin',

'colistimethate', 'dapsone', 'daptomycin', 'demeclocycline', 'dicloxacillin', 'doxycycline',

'efavirenz', 'ertapenem', 'erythromycin', 'erythromycin', 'ethambutol', 'fluconazole', 'gentamicin',

'hydroxychloroquine', 'imipenem', 'isoniazid', 'itraconazole', 'ketoconazole', 'lamivudine', 'levofloxacin',

'linezolid', 'meropenem', 'methenamine', 'metronidazole', 'minocycline', 'nafcillin',

'neomycin', 'nevirapine', 'nitrofurantoin', 'nystatin', 'oseltamivir', '

penicillin', 'pentamidine', 'piperacillin-tazobactam (single)', 'pyrazinamide', 'ribavirin',

'rifabutin', 'rifampin', 'ritonavir', 'sulfamethoxazole/trimethoprim', 'sulfasalazine',

'tenofovir', 'terbinafine', 'tetracycline', 'tigecycline', 'tobramycin', 'trimethoprim',

'valacyclovir', 'vancomycin', 'voriconazole'

)

and ROUTE IN ('iv','PO')

AND Real_Date_Time >'6/1/2013'

and ADMIN_STATUS ='admin'

Sean Lange SSC Guru Points: 286590 More actions · Answer 8

valeryk2000 (6/27/2013)
Ha! Sean, you elegantly rewrote my function (stollen from somwhere anyway).
I do not think that to use cte in my case is a good idea - I use this function within a select statement from a big table - not sure that cte can be used here

The only reason there is a cte there is for testing. I don't have a table with the values you posted so I just stuck them in a cte. It is merely an example of usage. That could a table, a cte, whatever.

They way you wrote the function and are using it is a scalar function. They are horrible for performance. Look at how I used the iTVF with cross apply instead of calling the function as a column. The performance benefits are HUGE!!!!

_______________________________________________________________

Need help? Help us help you.

Read the article at http://www.sqlservercentral.com/articles/Best+Practices/61537/ for best practices on asking questions.

Need to split a string? Try Jeff Modens splitter http://www.sqlservercentral.com/articles/Tally+Table/72993/.

Cross Tabs and Pivots, Part 1 – Converting Rows to Columns - http://www.sqlservercentral.com/articles/T-SQL/63681/
Cross Tabs and Pivots, Part 2 - Dynamic Cross Tabs - http://www.sqlservercentral.com/articles/Crosstab/65048/
Understanding and Using APPLY (Part 1) - http://www.sqlservercentral.com/articles/APPLY/69953/
Understanding and Using APPLY (Part 2) - http://www.sqlservercentral.com/articles/APPLY/69954/

valeryk2000 SSCarpal Tunnel Points: 4245 More actions · Answer 9

valeryk2000

SSCarpal Tunnel

Points: 4245

June 28, 2013 at 9:18 am

#1628326

Ok. I'll try it (never tried before)

valeryk2000 SSCarpal Tunnel Points: 4245 More actions · Answer 10

Sean, I hate to look stupid - but this is a quality not easy to hide ...

I was not able to use iTVF in my query ... alas ...

Luis Cazares SSC Guru Points: 183706 More actions · Answer 11

Please post your query and the problem you had so we can help you. 😉

Luis C.
General Disclaimer:
Are you seriously taking the advice and code from someone from the internet without testing it? Do you at least understand it? Or can it easily kill your server?

How to post data/code on a forum to get the best help: Option 1 / Option 2

ChrisM@Work SSC Guru Points: 186127 More actions · Answer 12

valeryk2000 (7/1/2013)
Sean, I hate to look stupid - but this is a quality not easy to hide ...
I was not able to use iTVF in my query ... alas ...

I'm sure we can change that...

^{“Write the query the simplest way. If through testing it becomes clear that the performance is inadequate, consider alternative query forms.” - Gail Shaw}

For fast, accurate and documented assistance in answering your questions, please read this article.
Understanding and using APPLY, (I) and (II) Paul White
Hidden RBAR: Triangular Joins / The "Numbers" or "Tally" Table: What it is and how it replaces a loop Jeff Moden