Ignore reading signs

Question

Ignore reading signs

Peter Kruis

Mr or Mrs. 500

Points: 577
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December 28, 2016 at 5:28 am

#324696

I am in need of a way to ignore reading signs, for example:
- I search on (like?) 921996 it will find the record with 92.1996 or 1219!96
Is there a way to achieve this?

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Lowell SSC Guru Points: 323504 More actions · Answer 1

not efficiently, because you would have to manipulate each column value.

what are we doing? stripping out just two specific values? stripping all non numeric characters? what about alpha characters?

with a function on a column name(rated one of the top 3 bad practices),

it will require a table scan every time you query, can be costly time wise and not very efficient...it's a table scan, pulling all data into memory so it can be manipulated to strip out characters.

on a trivial table like my example below, it's quick enough to not be relevant, but do this to a million row table,and your performance drops dramatically into tens of minutes, which is why I mention the alternatives below

IF OBJECT_ID('tempdb.[dbo].[#Temp]') IS NOT NULL

DROP TABLE [dbo].[#Temp]

GO

CREATE TABLE [dbo].[#Temp] (

[ID] INT NOT NULL,

[Animal] VARCHAR(30) NOT NULL,

[SignToScan] VARCHAR(30) NOT NULL)

INSERT INTO [#Temp]([ID],[Animal],[SignToScan])

SELECT '34','parrot','1219!96' UNION ALL

SELECT '52','ground hog','92.1996' UNION ALL

SELECT '47','marmoset','' UNION ALL

SELECT '85','chameleon','9219!96' UNION ALL

SELECT '84','whale','14.22!54' UNION ALL

SELECT '182','tapir','9m219!96'

--Two different examples below

--replace only two specific ones

SELECT *,REPLACE(REPLACE([SignToScan],'.',''),'!','')

FROM [#Temp]

WHERE REPLACE(REPLACE([SignToScan],'.',''),'!','') LIKE '921996%'

--replace anything non-numeric, so it strips out the 'm' in the tapir example

SELECT *

FROM [#Temp]

CROSS APPLY master.dbo.[StripNonNumeric_ITVF]([SignToScan]) AS [snni]

WHERE [snni].[CleanedText] LIKE '921996%'

so to be efficient, you want another column with the "Cleaned" text.

can you either clean the actual column, or add a new column?

a permanent one with the clean data is best, then you can easily index it.

An alternative is you could try to add a persisted, calculated column which strips the characters out, and then try to index tat.

yet another alternative is to create a view with the data all cleaned up, and then add an index on the view.

which ones work, and the way to tackle it, depends on your real data and requirements

Lowell

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Eric M Russell SSC Guru Points: 125519 More actions · Answer 2

The following is an example of Lowell's suggestion about implementing a computed column (ie: NonSignedProductCode). You can then create an index on that column and use it for searching.

Whether computed column is persisted is optional and debatable. I'm thinking that if the column is indexed, it can be non-persisted without a performance impact, if it's not included in the resultset.

CREATE TABLE Product

(

ProductCode VARCHAR(20) NOT NULL,

NonSignedProductCode

AS CAST(REPLACE(REPLACE(ProductCode,'.',''),'!','') AS VARCHAR(20))

);

CREATE INDEX IX_NonSignedProductCode

ON dbo.Product ( NonSignedProductCode );

SELECT ProductCode FROM Product WHERE NonSignedProductCode = '997223';

"Do not seek to follow in the footsteps of the wise. Instead, seek what they sought." - Matsuo Basho

Jeff Moden SSC Guru Points: 1003851 More actions · Answer 3

peter 67432 (12/28/2016)
I am in need of a way to ignore reading signs, for example:
- I search on (like?) 921996 it will find the record with 92.1996 or 1219!96
Is there a way to achieve this?

It it's uber important, create a persisted computed column on the table that strips all non digit characters from the column and use that to search on.

--Jeff Moden

RBAR is pronounced "ree-bar" and is a "Modenism" for Row-By-Agonizing-Row.
First step towards the paradigm shift of writing Set Based code:
________Stop thinking about what you want to do to a ROW... think, instead, of what you want to do to a COLUMN.

Change is inevitable... Change for the better is not.

Helpful Links:
How to post code problems
How to Post Performance Problems
Create a Tally Function (fnTally)

Peter Kruis Mr or Mrs. 500 Points: 577 More actions · Answer 4

Peter Kruis

Mr or Mrs. 500

Points: 577

January 2, 2017 at 5:10 am

#1920256

Thanks for the help, I will add a computed column.

Ed Wagner SSC Guru Points: 287024 More actions · Answer 5

peter 67432 (1/2/2017)
Thanks for the help, I will add a computed column.

Like Jeff said, consider making it a persisted one.

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