Search a string in a text with number of occurrences

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Search a string in a text with number of occurrences

SQL_Hunt

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March 29, 2015 at 4:27 pm

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Comments posted to this topic are about the item Search a string in a text with number of occurrences
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DonlSimpson SSCertifiable Points: 7043 More actions · Answer 1

Here's an alternative that uses a tally table:

;with dataLen as (select len(@inputString) i, len(@searchString) s)

select

'POSITION OF THE SEARCH STRING >> "' + @searchString + '" IS AT :' + cast(tt.i as varchar(100)),

count(tt.i) over (partition by null) numberFound

from dbo.talleyTable(len(@inputString)) tt

cross join dataLen dl

where tt.i between 1 and (dl.i - dl.s + 1)

and left(right(@inputString, dl.i - tt.i + 1), dl.s) = @searchString;

Don Simpson

I'm not sure about Heisenberg.

kdyess SSC Rookie Points: 38 More actions · Answer 2

Adam Machanic has a clr table valued function to split a string on a delimiter(http://sqlblog.com/blogs/adam_machanic/archive/2009/04/26/faster-more-scalable-sqlclr-string-splitting.aspx). Here's an adaptation of his clr that I put together in vb.net to get to the same information your procedure does in a different way that I think is a little bit more flexible. Just another thought on solving the problem.

Imports System

Imports System.Data

Imports System.Data.SqlClient

Imports System.Data.SqlTypes

Imports Microsoft.SqlServer.Server

Partial Public Class UserDefinedFunctions

Public Class stringManipulation

Implements IEnumerator

Private inputString As String

Private delimiter As String

Private nextPos As Integer

Private lastPos As Integer

Private stringProp As New stringProperties()

Public Sub New(inputString As String, delimiter As String)

Me.inputString = inputString

Me.delimiter = delimiter

Me.lastPos = -1

Me.nextPos = -1

End Sub

Public ReadOnly Property Current As Object Implements System.Collections.IEnumerator.Current

Get

Return DirectCast(stringProp, Object)

End Get

End Property

Public Function MoveNext() As Boolean Implements System.Collections.IEnumerator.MoveNext

If (nextPos >= inputString.Length) Then

Return False

Else

lastPos = nextPos + delimiter.Length

If (lastPos = inputString.Length) Then

Return False

End If

nextPos = inputString.IndexOf(delimiter, lastPos)

If nextPos = -1 Then

Return False

Else

stringProp.sequenceProp += 1

stringProp.indexPositionProp = nextPos + 1

End If

Return True

End If

End Function

Public Sub Reset() Implements System.Collections.IEnumerator.Reset

Me.lastPos = -1

Me.nextPos = -1

End Sub

End Class

Public Class stringProperties

Private sequence As Integer

Private indexPosition As Integer

Public Property sequenceProp() As Integer

Get

Return Me.sequence

End Get

Set(value As Integer)

Me.sequence = value

End Set

End Property

Public Property indexPositionProp() As Integer

Get

Return Me.indexPosition

End Get

Set(value As Integer)

Me.indexPosition = value

End Set

End Property

End Class

<Microsoft.SqlServer.Server.SqlFunction(FillRowMethodName:="findString_fillRow", _

TableDefinition:="sequence int, indexPosition int")> _

Public Shared Function findString(

inputString As SqlString,

<SqlFacet(MaxSize:=100)> delimiter As SqlString

) As IEnumerator

If inputString.IsNull Or delimiter.IsNull Or delimiter.ToString.Length > inputString.ToString.Length Then

Return (New stringManipulation("", ","))

Else

Return (New stringManipulation(inputString.ToString, delimiter.ToString))

End If

End Function

Public Shared Sub findString_fillRow(strCollectionObj As Object, ByRef sequence As SqlInt32, ByRef indexPosition As SqlInt32)

Dim stringProps As stringProperties = DirectCast(strCollectionObj, stringProperties)

sequence = stringProps.sequenceProp

indexPosition = stringProps.indexPositionProp

End Sub

End Class

Here's example results for finding the sql index of every space in the string passed to the tvf:

SELECT *

FROM dbo.findString('Here Are The Laws You Need To Know If You Bought A Defective Product',' ')

Here's some test data followed by several examples of manipulating the data returned by the tvf. jalopnikHeadline refers to headlines found on http://www.jalopnik.com/:

IF OBJECT_ID(N'dbo.findStringTest',N'U') IS NOT NULL

DROP TABLE dbo.findStringTest

GO

CREATE TABLE dbo.findStringTest

(

[id] TINYINT IDENTITY(1,1) NOT NULL

,[jalopnikHeadline] VARCHAR(255) NOT NULL

,CONSTRAINT pk_findStringTest PRIMARY KEY CLUSTERED([id])

)

GO

INSERT INTO dbo.findStringTest

(

[jalopnikHeadline]

)

SELECT 'Apple''s Sensor-Covered Minivans Are Invading Texas'

UNION

SELECT 'Exactly Where The 2015 Ford F-150 Lost Weight, Below The Aluminum Body'

UNION

SELECT 'Oh, Good: We Might Hear More Music From Lewis Hamilton About His Ex'

UNION

SELECT 'Tech Blogger Says He Watched As Youths Wirelessly Broke Into His Car'

UNION

SELECT 'Here Are The Laws You Need To Know If You Bought A Defective Product'

UNION

SELECT 'How To Drive An Illegal-*** Car For Years Without Getting Busted'

UNION

SELECT 'Here Are Ten Of The Best Dream Cars On eBay For Less Than $80,000'

UNION

SELECT 'Let American Hero Jack Diamond Teach You How To Flip A Car Properly'

GO

-- Review the inserted data

SELECT *

FROM dbo.findStringTest

-- Full results returned by the tvf with cross apply

SELECT *

FROM dbo.findStringTest

OUTER APPLY dbo.findString([jalopnikHeadline],' ') fs

-- Returning comma separated indexes for a single string into a variable

DECLARE @searchIndexes NVARCHAR(100) = ''

SELECT @searchIndexes += ',' + CAST(fs.[indexPosition] AS VARCHAR)

FROM dbo.findString('This is a test string for returning the position of a delimiter in a string n times ',' ') fs

PRINT('@searchIndexes: ' + SUBSTRING(@searchIndexes,2,LEN(@searchIndexes)))

-- Returning comma separated indexes for a single string using xml path

SELECT SUBSTRING((

SELECT ',' + CAST([indexPosition] AS VARCHAR)

FROM dbo.findString('This is a test string for returning the position of a delimiter in a string n times ',' ')

FOR XML PATH('')

),2,4000)

-- Returning comma separated indexes for strings in a query

SELECT *

,(SELECT SUBSTRING((

SELECT ',' + CAST(fs.[indexPosition] AS VARCHAR)

FROM dbo.findStringTest fsti

OUTER APPLY dbo.findString(fsti.[jalopnikHeadline],' ') fs

WHERE fsti.[id] = fst.[id]

FOR XML PATH('')

),2,4000)) AS [searchIndexes]

FROM dbo.findStringTest fst

-- Pivot data returned from the function from multiple rows into one row per id with a column for each index

;WITH indexScrapedMaster

AS

(

SELECT [id],[jalopnikHeadline] AS [inputString]

,fs.[sequence],fs.[indexPosition]

FROM dbo.findStringTest

OUTER APPLY dbo.findString([jalopnikHeadline],' ') fs

)

SELECT [id],[inputString]

[1],[2],[3],[4],[5]

,[6],[7],[8],[9],[10]

,[11],[12],[13],[14],[15]

FROM

(

SELECT [id],[inputString]

,CAST([sequence] AS VARCHAR) AS [indexSequence]

,[indexPosition]

FROM indexScrapedMaster

) st

PIVOT

(

MAX([indexPosition]) FOR [indexSequence] IN

(

[1],[2],[3],[4],[5]

,[6],[7],[8],[9],[10]

,[11],[12],[13],[14],[15]

)

) pvt

ORDER BY [id]

GO

IF OBJECT_ID(N'dbo.findStringTest',N'U') IS NOT NULL

DROP TABLE dbo.findStringTest

GO

Luis Cazares SSC Guru Points: 183698 More actions · Answer 3

Just adding a solution that goes a little bit further than Don's.

WITH

E(n) AS(

SELECT n FROM (VALUES(0),(0),(0),(0),(0),(0),(0),(0),(0),(0)) E(n) --10 rows

),

E2(n) AS(

SELECT a.n FROM E a, E b --10 x 10 = 100 rows

),

E4(n) AS(

SELECT a.n FROM E2 a, E2 b --100 x 100 = 10,000 rows

),

cteTally AS(

SELECT TOP(len(@inputString) - len(@searchString) + 1) --Limit the number of rows

ROW_NUMBER() OVER( ORDER BY (SELECT NULL)) i

FROM E4

),

cteResults AS(

select

CAST( count(tt.i) over (partition by null) AS varchar(5)) numberFound ,

tt.i

from cteTally tt

where SUBSTRING(@inputString, tt.i, len(@searchString)) = @searchString

)

SELECT Result

FROM cteResults

CROSS APPLY( VALUES(1, 'POSITION OF THE SEARCH STRING >> "' + @searchString + '" IS AT : ' + cast(i as varchar(5))),

(2, 'THE SEARCHED STRING APPEARED >> ' + numberFound + ' TIMES'),

(3, '**** END OF SEARCH ***') ) cav(roworder, Result)

GROUP BY Result, roworder

ORDER BY roworder, MIN(i)

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

Alan Burstein SSC Guru Points: 61136 More actions · Answer 4

I know thread is a little old but this is exactly the kind of thing you could do with a good NGrams8K function. Here's the function:

CREATE FUNCTION dbo.NGrams8k

(

@string varchar(8000), -- Input string

@N int -- requested token size

)

/****************************************************************************************

Purpose:

A character-level @N-Grams function that outputs a contiguous stream of @N-sized tokens

based on an input string (@string). Accepts strings up to 8000 varchar characters long.

For more information about N-Grams see: http://en.wikipedia.org/wiki/N-gram.

Compatibility:

SQL Server 2008+ and Azure SQL Database

Syntax:

--===== Autonomous

SELECT position, token FROM dbo.NGrams8k(@string,@N);

--===== Against a table using APPLY

SELECT s.SomeID, ng.position, ng.string

FROM dbo.SomeTable s

CROSS APPLY dbo.NGrams8K(s.SomeValue,@N) ng;

Parameters:

@string = The input string to split into tokens.

@N = The size of each token returned.

Returns:

Position = bigint; the position of the token in the input string

token = varchar(8000); a @N-sized character-level N-Gram token

Examples:

--===== Turn the string, 'abcd' into unigrams, bigrams and trigrams

SELECT position, token FROM dbo.NGrams8k('abcd',1); -- unigrams (@N=1)

SELECT position, token FROM dbo.NGrams8k('abcd',2); -- bigrams (@N=2)

SELECT position, token FROM dbo.NGrams8k('abcd',3); -- trigrams (@N=1)

--===== How many times the substring "AB" appears in each record

DECLARE @table TABLE(stringID int identity primary key, string varchar(100));

INSERT @table(string) VALUES ('AB123AB'),('123ABABAB'),('!AB!AB!'),('AB-AB-AB-AB-AB');

SELECT string, occurances = COUNT(*)

FROM @table t

CROSS APPLY dbo.NGrams8k(t.string,2) ng

WHERE ng.token = 'AB'

GROUP BY string;

Developer Notes:

1. This function is not case sensitive

2. Many functions that use NGrams8k will see a huge performance gain when the optimizer

creates a parallel query plan. One way to get a parallel query plan (if the optimizer

does not chose one) is to use make_parallel by Adam Machanic which can be found here:

sqlblog.com/blogs/adam_machanic/archive/2013/07/11/next-level-parallel-plan-porcing.aspx

3. When @N is less than 1 or greater than the datalength of the input string then no

tokens (rows) are returned.

4. This function can also be used as a tally table with the position column being your

"N" row. To do so use REPLICATE to create an imaginary string, then use NGrams8k to

split it into unigrams then only return the position column. NGrams8k will get you up

to 8000 numbers. There will be no performance penalty for sorting by position in

ascending order but there is for sorting in descending order. To get the numbers in

descending order without forcing a sort in the query plan use the following formula:

N = <highest number>-position+1.

Pseudo Tally Table Examples:

--===== (1) Get the numbers 1 to 100 in ascending order:

SELECT N = position FROM dbo.NGrams8k(REPLICATE(0,100),1);

--===== (2) Get the numbers 1 to 100 in descending order:

DECLARE @maxN int = 100;

SELECT N = @maxN-position+1

FROM dbo.NGrams8k(REPLICATE(0,@maxN),1)

ORDER BY position;

-- note: you don't need a variable, I used one to make the example easier to understand.

----------------------------------------------------------------------------------------

Revision History:

Rev 00 - 20140310 - Initial Development - Alan Burstein

Rev 01 - 20150522 - Removed DQS N-Grams functionality, improved iTally logic. Also Added

conversion to bigint in the TOP logic to remove implicit conversion

to bigint - Alan Burstein

Rev 03 - 20150909 - Added logic to only return values if @N is greater than 0 and less

than the length of @string. Updated comment section. - Alan Burstein

Rev 04 - 20151029 - Added ISNULL logic to the TOP clause for the @string and @N

parameters to prevent a NULL string or NULL @N from causing "an

improper value" being passed to the TOP clause. - Alan Burstein

****************************************************************************************/

RETURNS TABLE WITH SCHEMABINDING AS RETURN

WITH

L1(N) AS

(

SELECT 1

FROM (VALUES -- 90 NULL values used to create the CTE Tally table

(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),

(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL)

) t(N)

),

iTally(N) AS -- my cte Tally table

(

SELECT TOP(ABS(CONVERT(BIGINT,(DATALENGTH(ISNULL(@string,''))-(ISNULL(@N,1)-1)),0)))

ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) -- Order by a constant to avoid a sort

FROM L1 a CROSS JOIN L1 b -- cartesian product for 8100 rows (90^2)

)

SELECT

position = N, -- position of the token in the string(s)

token = SUBSTRING(@string,CAST(N AS int),@N) -- the @N-Sized token

FROM iTally

WHERE @N > 0 AND @N <= DATALENGTH(@string); -- force the function to ignore a "bad @N"

Here's a purely set-based way to find a string within a string along with it's location in the string.

DECLARE

@inputString varchar(800) = 'abc123xyz123',

@searchString varchar(800) = '123';

SELECT *

FROM dbo.NGrams8k(@inputString, LEN(@searchstring))

WHERE token = @searchstring;

"I cant stress enough the importance of switching from a sequential files mindset to set-based thinking. After you make the switch, you can spend your time tuning and optimizing your queries instead of maintaining lengthy, poor-performing code."

-- Itzik Ben-Gan 2001