问题
I have a table Persons with personaldata and so on. There are lots of columns but the once of interest here are: addressindex, lastname and firstname where addressindex is a unique address drilled down to the door of the apartment.
So if I have 'like below' two persons with the lastname and one the firstnames are the same they are most likely duplicates.
I need a way to list these duplicates.
tabledata:
personid 1
firstname "Carl"
lastname "Anderson"
addressindex 1
personid 2
firstname "Carl Peter"
lastname "Anderson"
addressindex 1
I know how do this if I were to match exactly on all columns but I need fuzzy match to do the trick with (from the above example) a result like:
Row personid addressindex lastname firstname
1 2 1 Anderson Carl Peter
2 1 1 Anderson Carl
.....
Any hints on how to solve this in a good way?
回答1:
I've found that the stuff SQL Server gives you to do fuzzy matching is pretty clunky. I've had really good luck with my own CLR functions using the Levenshtein distance algorithm and some weighting. Using that algorithm, I've then made a UDF called GetSimilarityScore that takes two strings and returns a score between 0.0 and 1.0. The closer to 1.0 the match is, the better. Then, query with a threshold of >=0.8 or so to get the most likely matches. Something like this:
if object_id('tempdb..#similar') is not null drop table #similar
select a.id, (
select top 1 x.id
from MyTable x
where x.id <> a.id
order by dbo.GetSimilarityScore(a.MyField, x.MyField) desc
) as MostSimilarId
into #similar
from MyTable a
select *, dbo.GetSimilarityScore(a.MyField, c.MyField)
from MyTable a
join #similar b on a.id = b.id
join MyTable c on b.MostSimilarId = c.id
Just don't do it with really large tables. It's a slow process.
Here's the CLR UDFs:
''' <summary>
''' Compute the distance between two strings.
''' </summary>
''' <param name="s1">The first of the two strings.</param>
''' <param name="s2">The second of the two strings.</param>
''' <returns>The Levenshtein cost.</returns>
<Microsoft.SqlServer.Server.SqlFunction()> _
Public Shared Function ComputeLevenstheinDistance(ByVal string1 As SqlString, ByVal string2 As SqlString) As SqlInt32
If string1.IsNull OrElse string2.IsNull Then Return SqlInt32.Null
Dim s1 As String = string1.Value
Dim s2 As String = string2.Value
Dim n As Integer = s1.Length
Dim m As Integer = s2.Length
Dim d As Integer(,) = New Integer(n, m) {}
' Step 1
If n = 0 Then Return m
If m = 0 Then Return n
' Step 2
For i As Integer = 0 To n
d(i, 0) = i
Next
For j As Integer = 0 To m
d(0, j) = j
Next
' Step 3
For i As Integer = 1 To n
'Step 4
For j As Integer = 1 To m
' Step 5
Dim cost As Integer = If((s2(j - 1) = s1(i - 1)), 0, 1)
' Step 6
d(i, j) = Math.Min(Math.Min(d(i - 1, j) + 1, d(i, j - 1) + 1), d(i - 1, j - 1) + cost)
Next
Next
' Step 7
Return d(n, m)
End Function
''' <summary>
''' Returns a score between 0.0-1.0 indicating how closely two strings match. 1.0 is a 100%
''' T-SQL equality match, and the score goes down from there towards 0.0 for less similar strings.
''' </summary>
<Microsoft.SqlServer.Server.SqlFunction()> _
Public Shared Function GetSimilarityScore(string1 As SqlString, string2 As SqlString) As SqlDouble
If string1.IsNull OrElse string2.IsNull Then Return SqlInt32.Null
Dim s1 As String = string1.Value.ToUpper().TrimEnd(" "c)
Dim s2 As String = string2.Value.ToUpper().TrimEnd(" "c)
If s1 = s2 Then Return 1.0F ' At this point, T-SQL would consider them the same, so I will too
Dim flatLevScore As Double = InternalGetSimilarityScore(s1, s2)
Dim letterS1 As String = GetLetterSimilarityString(s1)
Dim letterS2 As String = GetLetterSimilarityString(s2)
Dim letterScore As Double = InternalGetSimilarityScore(letterS1, letterS2)
'Dim wordS1 As String = GetWordSimilarityString(s1)
'Dim wordS2 As String = GetWordSimilarityString(s2)
'Dim wordScore As Double = InternalGetSimilarityScore(wordS1, wordS2)
If flatLevScore = 1.0F AndAlso letterScore = 1.0F Then Return 1.0F
If flatLevScore = 0.0F AndAlso letterScore = 0.0F Then Return 0.0F
' Return weighted result
Return (flatLevScore * 0.2F) + (letterScore * 0.8F)
End Function
Private Shared Function InternalGetSimilarityScore(s1 As String, s2 As String) As Double
Dim dist As SqlInt32 = ComputeLevenstheinDistance(s1, s2)
Dim maxLen As Integer = If(s1.Length > s2.Length, s1.Length, s2.Length)
If maxLen = 0 Then Return 1.0F
Return 1.0F - Convert.ToDouble(dist.Value) / Convert.ToDouble(maxLen)
End Function
''' <summary>
''' Sorts all the alpha numeric characters in the string in alphabetical order
''' and removes everything else.
''' </summary>
Private Shared Function GetLetterSimilarityString(s1 As String) As String
Dim allChars = If(s1, "").ToUpper().ToCharArray()
Array.Sort(allChars)
Dim result As New StringBuilder()
For Each ch As Char In allChars
If Char.IsLetterOrDigit(ch) Then
result.Append(ch)
End If
Next
Return result.ToString()
End Function
''' <summary>
''' Removes all non-alpha numeric characters and then sorts
''' the words in alphabetical order.
''' </summary>
Private Shared Function GetWordSimilarityString(s1 As String) As String
Dim words As New List(Of String)()
Dim curWord As StringBuilder = Nothing
For Each ch As Char In If(s1, "").ToUpper()
If Char.IsLetterOrDigit(ch) Then
If curWord Is Nothing Then
curWord = New StringBuilder()
End If
curWord.Append(ch)
Else
If curWord IsNot Nothing Then
words.Add(curWord.ToString())
curWord = Nothing
End If
End If
Next
If curWord IsNot Nothing Then
words.Add(curWord.ToString())
End If
words.Sort(StringComparer.OrdinalIgnoreCase)
Return String.Join(" ", words.ToArray())
End Function
回答2:
In addition to the other good info here, you might want to consider using the Double Metaphone phonetic algorithm which is generally considered to be better than SOUNDEX.
Tim Pfeiffer details an implementation in SQL in his article Double Metaphone Sounds Great Convert the C++ Double Metaphone algorithm to T-SQL (originally in SQL Mag & then in SQL Server Pro).
That will assist in matching names with slight misspellings, e.g., Carl vs. Karl.
Update: The actual downloadable code seems to be gone, but here's an implementation found on a github repo that appears to have cloned the original code
回答3:
I would use SQL Server Full Text Indexing, which will allow you to do searches and return things that not only contain the word but also may have a misspelling.
回答4:
Since the first release of Master Data Services, you've got access to more advanced fuzzy logic algorithms than what SOUNDEX implements. So provided that you've got MDS installed, you'll be able to find a function called Similarity() in the mdq schema (MDS database).
More info on how it works: http://blog.hoegaerden.be/2011/02/05/finding-similar-strings-with-fuzzy-logic-functions-built-into-mds/
回答5:
I personally use a CLR implementation of the Jaro-Winkler algorithm which seems to work pretty well - it struggles a bit with strings longer than about 15 characters and doesn't like matching email addresses but otherwise is quite good - full implementation guide can be found here
If you are unable to use CLR functions for whatever reasons, maybe you could try running the data through an SSIS package (using the fuzzy transformation lookup) - detailed here
回答6:
Part 2 of the code For the link in Redfilter Answer:
References:
https://github.com/mb16/geocoderNet/blob/master/build/sql/doubleMetaphone.sql
BEGIN
SET @MP1 = @MP1 + 'N'
SET @MP2 = @MP2 + 'KN'
END
ELSE
BEGIN
SET @MP1 = @MP1 + 'KN'
SET @MP2 = @MP2 + 'KN'
END
END
SET @CurrentPosition = @CurrentPosition + 2
END
--'tagliaro'
ELSE IF (dbo.fnStringAt((@CurrentPosition + 1),@Word,'LI')=1) AND
(dbo.fnSlavoGermanic(@Word)=0)
BEGIN
SET @MP1 = @MP1 + 'KL'
SET @MP2 = @MP2 + 'L'
SET @CurrentPosition = @CurrentPosition + 2
END
-- -ges-,-gep-,-gel-, -gie- at beginning
-- This call to fnStringAt() is the 'worst case' in number of values passed. A UDF that used DEFAULT values instead of
-- a multi-valued argument would require ten DEFAULT arguments for EP, EB, EL, etc. (assuming the first was not defined with a DEFAULT).
ELSE IF ((@CurrentPosition = 1)
AND ((SUBSTRING(@Word,@CurrentPosition + 1,1) = 'Y')
OR (dbo.fnStringAt((@CurrentPosition +
1),@Word,'ES,EP,EB,EL,EY,IB,IL,IN,IE,EI,ER')=1)) )
BEGIN
SET @MP1 = @MP1 + 'K'
SET @MP2 = @MP2 + 'J'
SET @CurrentPosition = @CurrentPosition + 2
END
-- -ger-, -gy-
ELSE IF (((dbo.fnStringAt((@CurrentPosition + 1), @Word, 'ER')=1) OR
(SUBSTRING(@Word,@CurrentPosition + 1,1) = 'Y'))
AND (dbo.fnStringAt(1, @Word, 'DANGER,RANGER,MANGER')=0)
AND (dbo.fnStringAt((@CurrentPosition - 1), @Word,
'E,I,RGY,OGY')=0) )
BEGIN
SET @MP1 = @MP1 + 'K'
SET @MP2 = @MP2 + 'J'
SET @CurrentPosition = @CurrentPosition + 2
END
-- italian e.g, 'biaggi'
ELSE IF (dbo.fnStringAt((@CurrentPosition + 1),@Word,'E,I,Y')=1) OR
(dbo.fnStringAt((@CurrentPosition - 1),@Word,'AGGI,OGGI')=1)
BEGIN
--obvious germanic
IF ((dbo.fnStringAt(1,@Word,'VAN ,VON ,SCH')=1)
OR (dbo.fnStringAt((@CurrentPosition + 1),@Word,'ET')=1))
BEGIN
SET @MP1 = @MP1 + 'K'
SET @MP2 = @MP2 + 'K'
END
ELSE
BEGIN
--always soft if french ending
IF (dbo.fnStringAt((@CurrentPosition + 1),@Word,'IER ')=1)
BEGIN
SET @MP1 = @MP1 + 'J'
SET @MP2 = @MP2 + 'J'
END
ELSE
BEGIN
SET @MP1 = @MP1 + 'J'
SET @MP2 = @MP2 + 'K'
END
END
SET @CurrentPosition = @CurrentPosition + 2
END
ELSE
BEGIN
IF (SUBSTRING(@Word,@CurrentPosition + 1,1) = 'G')
BEGIN
SET @CurrentPosition = @CurrentPosition + 2
END
ELSE
BEGIN
SET @CurrentPosition = @CurrentPosition + 1
END
SET @MP1 = @MP1 + 'K'
SET @MP2 = @MP2 + 'K'
END
END
ELSE IF @CurrentChar = 'H'
BEGIN
--only keep if first & before vowel or btw. 2 vowels
IF (((@CurrentPosition = 1) OR
(dbo.fnIsVowel(SUBSTRING(@Word,@CurrentPosition - 1,1))=1))
AND (dbo.fnIsVowel(SUBSTRING(@Word,@CurrentPosition + 1,1))=1))
BEGIN
SET @MP1 = @MP1 + 'H'
SET @MP2 = @MP2 + 'H'
SET @CurrentPosition = @CurrentPosition + 2
END
--also takes care of 'HH'
ELSE
BEGIN
SET @CurrentPosition = @CurrentPosition + 1
END
END
ELSE IF @CurrentChar = 'J'
BEGIN
--obvious spanish, 'jose', 'san jacinto'
IF (dbo.fnStringAt(@CurrentPosition,@Word,'JOSE')=1) OR
(dbo.fnStringAt(1,@Word,'SAN ')=1)
BEGIN
IF (((@CurrentPosition = 1) AND (SUBSTRING(@Word,@CurrentPosition
+ 4,1) = ' ')) OR (dbo.fnStringAt(1,@Word,'SAN ')=1) )
BEGIN
SET @MP1 = @MP1 + 'H'
SET @MP2 = @MP2 + 'H'
END
ELSE
BEGIN
SET @MP1 = @MP1 + 'J'
SET @MP2 = @MP2 + 'H'
END
SET @CurrentPosition = @CurrentPosition + 1
END
ELSE IF ((@CurrentPosition = 1) AND
(dbo.fnStringAt(@CurrentPosition,@Word,'JOSE')=0))
BEGIN
SET @MP1 = @MP1 + 'J'
--Yankelovich/Jankelowicz
SET @MP2 = @MP2 + 'A'
--it could happen!
IF (SUBSTRING(@Word,@CurrentPosition + 1,1) = 'J')
BEGIN
SET @CurrentPosition = @CurrentPosition + 2
END
ELSE
BEGIN
SET @CurrentPosition = @CurrentPosition + 1
END
END
ELSE
BEGIN
--spanish pron. of e.g. 'bajador'
IF( (dbo.fnIsVowel(SUBSTRING(@Word,@CurrentPosition - 1,1))=1)
AND (dbo.fnSlavoGermanic(@Word)=0)
AND ((SUBSTRING(@Word,@CurrentPosition + 1,1) = 'A') OR
(SUBSTRING(@Word,@CurrentPosition + 1,1) = 'O')))
BEGIN
SET @MP1 = @MP1 + 'J'
SET @MP2 = @MP2 + 'H'
END
ELSE
BEGIN
IF (@CurrentPosition = @WordLength)
BEGIN
SET @MP1 = @MP1 + 'J'
SET @MP2 = @MP2 + ''
END
ELSE
BEGIN
IF ((dbo.fnStringAt((@CurrentPosition + 1), @Word,
'L,T,K,S,N,M,B,Z')=0)
AND (dbo.fnStringAt((@CurrentPosition - 1), @Word,
'S,K,L')=0))
BEGIN
SET @MP1 = @MP1 + 'J'
SET @MP2 = @MP2 + 'J'
END
END
END
--it could happen!
IF (SUBSTRING(@Word,@CurrentPosition + 1,1) = 'J')
BEGIN
SET @CurrentPosition = @CurrentPosition + 2
END
ELSE
BEGIN
SET @CurrentPosition = @CurrentPosition + 1
END
END
END
ELSE IF @CurrentChar = 'K'
BEGIN
IF (SUBSTRING(@Word,@CurrentPosition + 1,1) = 'K')
BEGIN
SET @CurrentPosition = @CurrentPosition + 2
END
ELSE
BEGIN
SET @CurrentPosition = @CurrentPosition + 1
END
SET @MP1 = @MP1 + 'K'
SET @MP2 = @MP2 + 'K'
END
ELSE IF @CurrentChar = 'L'
BEGIN
IF (SUBSTRING(@Word,@CurrentPosition + 1,1) = 'L')
BEGIN
--spanish e.g. 'cabrillo', 'gallegos'
IF (((@CurrentPosition = (@WordLength - 3))
AND (dbo.fnStringAt((@CurrentPosition -
1),@Word,'ILLO,ILLA,ALLE')=1))
OR (((dbo.fnStringAt((@WordLength - 1),@Word,'AS,OS')=1)
OR (dbo.fnStringAt(@WordLength,@Word,'A,O')=1))
AND (dbo.fnStringAt((@CurrentPosition -
1),@Word,'ALLE')=1)) )
BEGIN
SET @MP1 = @MP1 + 'L'
SET @MP2 = @MP2 + ''
SET @CurrentPosition = @CurrentPosition + 2
END
ELSE
BEGIN
SET @CurrentPosition = @CurrentPosition + 2
SET @MP1 = @MP1 + 'L'
SET @MP2 = @MP2 + 'L'
END
END
ELSE
BEGIN
SET @CurrentPosition = @CurrentPosition + 1
SET @MP1 = @MP1 + 'L'
SET @MP2 = @MP2 + 'L'
END
END
ELSE IF @CurrentChar = 'M'
BEGIN
--'dumb','thumb'
IF (((dbo.fnStringAt((@CurrentPosition - 1), @Word,'UMB')=1)
AND (((@CurrentPosition + 1) = @WordLength) OR
(dbo.fnStringAt((@CurrentPosition + 2),@Word,'ER')=1)))
OR (SUBSTRING(@Word,@CurrentPosition + 1,1) = 'M') )
BEGIN
SET @CurrentPosition = @CurrentPosition + 2
END
ELSE
BEGIN
SET @CurrentPosition = @CurrentPosition + 1
END
SET @MP1 = @MP1 + 'M'
SET @MP2 = @MP2 + 'M'
END
ELSE IF @CurrentChar = 'N'
BEGIN
IF (SUBSTRING(@Word,@CurrentPosition + 1,1) = 'N')
BEGIN
SET @CurrentPosition = @CurrentPosition + 2
END
ELSE
BEGIN
SET @CurrentPosition = @CurrentPosition + 1
END
SET @MP1 = @MP1 + 'N'
SET @MP2 = @MP2 + 'N'
END
ELSE IF @CurrentChar = 'Ñ'
BEGIN
SET @CurrentPosition = @CurrentPosition + 1
SET @MP1 = @MP1 + 'N'
SET @MP2 = @MP2 + 'N'
END
ELSE IF @CurrentChar = 'P'
BEGIN
--What about Michelle Pfeiffer, star of Grease 2? Price-Pfister?, Pfizer?
--Don't just look for an 'F' next, what about 'topflight', helpful, campfire, leapfrog, stepfather
--Sorry, Mark Knopfler, I don't know how to help you
IF (SUBSTRING(@Word,@CurrentPosition + 1,1) = 'H')
OR ((@CurrentPosition = 1) AND
(SUBSTRING(@Word,@CurrentPosition + 1,1) = 'F') AND
(dbo.fnIsVowel(SUBSTRING(@Word,@CurrentPosition+2,1))=1))
BEGIN
SET @MP1 = @MP1 + 'F'
SET @MP2 = @MP2 + 'F'
SET @CurrentPosition = @CurrentPosition + 2
END
--also account for "campbell", "raspberry"
ELSE
BEGIN
IF (dbo.fnStringAt((@CurrentPosition + 1),@Word, 'P,B')=1)
BEGIN
SET @CurrentPosition = @CurrentPosition + 2
END
ELSE
BEGIN
SET @CurrentPosition = @CurrentPosition + 1
END
SET @MP1 = @MP1 + 'P'
SET @MP2 = @MP2 + 'P'
END
END
ELSE IF @CurrentChar = 'Q'
BEGIN
IF (SUBSTRING(@Word,@CurrentPosition + 1,1) = 'Q')
BEGIN
SET @CurrentPosition = @CurrentPosition + 2
END
ELSE
BEGIN
SET @CurrentPosition = @CurrentPosition + 1
END
SET @MP1 = @MP1 + 'K'
SET @MP2 = @MP2 + 'K'
END
ELSE IF @CurrentChar = 'R'
BEGIN
--QQ: Will SQL short circuit eval? Otherwise, I could try to read before string begins here...
--french e.g. 'rogier', but exclude 'hochmeier'
IF ((@CurrentPosition = @WordLength)
AND (dbo.fnSlavoGermanic(@Word)=0)
AND (dbo.fnStringAt((@CurrentPosition - 2), @Word, 'IE')=1)
AND (dbo.fnStringAt((@CurrentPosition - 4), @Word,
'ME,MA')=0))
BEGIN
SET @MP1 = @MP1 + ''
SET @MP2 = @MP2 + 'R'
END
ELSE
BEGIN
SET @MP1 = @MP1 + 'R'
SET @MP2 = @MP2 + 'R'
END
IF (SUBSTRING(@Word,@CurrentPosition + 1,1) = 'R')
BEGIN
SET @CurrentPosition = @CurrentPosition + 2
END
ELSE
BEGIN
SET @CurrentPosition = @CurrentPosition + 1
END
END
ELSE IF @CurrentChar = 'S'
BEGIN
--special cases 'island', 'isle', 'carlisle', 'carlysle'
IF (dbo.fnStringAt((@CurrentPosition - 1), @Word, 'ISL,YSL')=1)
BEGIN
SET @CurrentPosition = @CurrentPosition + 1
END
--special case 'sugar-'
ELSE IF ((@CurrentPosition = 1) AND (dbo.fnStringAt(@CurrentPosition,
@Word, 'SUGAR')=1))
BEGIN
SET @MP1 = @MP1 + 'X'
SET @MP2 = @MP2 + 'S'
SET @CurrentPosition = @CurrentPosition + 1
END
ELSE IF (dbo.fnStringAt(@CurrentPosition, @Word, 'SH')=1)
BEGIN
--germanic
IF (dbo.fnStringAt((@CurrentPosition + 1), @Word,
'HEIM,HOEK,HOLM,HOLZ')=1)
BEGIN
SET @MP1 = @MP1 + 'S'
SET @MP2 = @MP2 + 'S'
END
ELSE
BEGIN
SET @MP1 = @MP1 + 'X'
SET @MP2 = @MP2 + 'X'
END
SET @CurrentPosition = @CurrentPosition + 2
END
--italian & armenian
ELSE IF (dbo.fnStringAt(@CurrentPosition, @Word, 'SIO,SIA')=1) OR
(dbo.fnStringAt(@CurrentPosition, @Word, 'SIAN')=1)
BEGIN
IF (dbo.fnSlavoGermanic(@Word)=0)
BEGIN
SET @MP1 = @MP1 + 'S'
SET @MP2 = @MP2 + 'X'
END
ELSE
BEGIN
SET @MP1 = @MP1 + 'S'
SET @MP2 = @MP2 + 'S'
END
SET @CurrentPosition = @CurrentPosition + 3
END
--german & anglicisations, e.g. 'smith' match 'schmidt', 'snider' match 'schneider'
--also, -sz- in slavic language altho in hungarian it is pronounced 's'
ELSE IF (((@CurrentPosition = 1)
AND (dbo.fnStringAt((@CurrentPosition + 1), @Word, 'M,N,L,W')=1))
OR (dbo.fnStringAt((@CurrentPosition + 1), @Word, 'Z')=1))
BEGIN
SET @MP1 = @MP1 + 'S'
SET @MP2 = @MP2 + 'X'
IF (dbo.fnStringAt((@CurrentPosition + 1), @Word, 'Z')=1)
BEGIN
SET @CurrentPosition = @CurrentPosition + 2
END
ELSE
BEGIN
SET @CurrentPosition = @CurrentPosition + 1
END
END
ELSE IF (dbo.fnStringAt(@CurrentPosition, @Word, 'SC')=1)
BEGIN
--Schlesinger's rule
IF (SUBSTRING(@Word,@CurrentPosition + 2,1) = 'H')
BEGIN
--dutch origin, e.g. 'school', 'schooner'
IF (dbo.fnStringAt((@CurrentPosition + 3), @Word,
'OO,ER,EN,UY,ED,EM')=1)
BEGIN
--'schermerhorn', 'schenker'
IF (dbo.fnStringAt((@CurrentPosition + 3), @Word, 'ER,EN')=1)
BEGIN
SET @MP1 = @MP1 + 'X'
SET @MP2 = @MP2 + 'SK'
END
ELSE
BEGIN
SET @MP1 = @MP1 + 'SK'
SET @MP2 = @MP2 + 'SK'
END
SET @CurrentPosition = @CurrentPosition + 3
END
ELSE
BEGIN
IF ((@CurrentPosition = 1) AND
(dbo.fnIsVowel(SUBSTRING(@Word,3,1))=0) AND (SUBSTRING(@Word,3,1) <> 'W'))
BEGIN
SET @MP1 = @MP1 + 'X'
SET @MP2 = @MP2 + 'S'
END
ELSE
BEGIN
SET @MP1 = @MP1 + 'X'
SET @MP2 = @MP2 + 'X'
END
SET @CurrentPosition = @CurrentPosition + 3
END
END
ELSE IF (dbo.fnStringAt((@CurrentPosition + 2), @Word, 'I,E,Y')=1)
BEGIN
SET @MP1 = @MP1 + 'S'
SET @MP2 = @MP2 + 'S'
SET @CurrentPosition = @CurrentPosition + 3
END
ELSE
BEGIN
SET @MP1 = @MP1 + 'SK'
SET @MP2 = @MP2 + 'SK'
SET @CurrentPosition = @CurrentPosition + 3
END
END
ELSE
BEGIN
--french e.g. 'resnais', 'artois'
IF ((@CurrentPosition = @WordLength) AND
(dbo.fnStringAt((@CurrentPosition - 2), @Word, 'AI,OI')=1))
BEGIN
SET @MP1 = @MP1 + ''
SET @MP2 = @MP2 + 'S'
END
ELSE
BEGIN
SET @MP1 = @MP1 + 'S'
SET @MP2 = @MP2 + 'S'
END
IF (dbo.fnStringAt((@CurrentPosition + 1), @Word, 'S,Z')=1)
BEGIN
SET @CurrentPosition = @CurrentPosition + 2
END
ELSE
BEGIN
SET @CurrentPosition = @CurrentPosition + 1
END
END
END
ELSE IF @CurrentChar = 'T'
BEGIN
IF (dbo.fnStringAt(@CurrentPosition, @Word, 'TION,TIA,TCH')=1)
BEGIN
SET @MP1 = @MP1 + 'X'
SET @MP2 = @MP2 + 'X'
SET @CurrentPosition = @CurrentPosition + 3
END
ELSE IF (dbo.fnStringAt(@CurrentPosition, @Word, 'TH,TTH')=1)
BEGIN
--special case 'thomas', 'thames' or germanic
IF (dbo.fnStringAt((@CurrentPosition + 2), @Word, 'OM,AM')=1)
OR (dbo.fnStringAt(1, @Word, 'VAN ,VON ,SCH')=1)
BEGIN
SET @MP1 = @MP1 + 'T'
SET @MP2 = @MP2 + 'T'
END
ELSE
BEGIN
SET @MP1 = @MP1 + '0'
SET @MP2 = @MP2 + 'T'
END
SET @CurrentPosition = @CurrentPosition + 2
END
ELSE
BEGIN
IF (dbo.fnStringAt((@CurrentPosition + 1), @Word, 'T,D')=1)
BEGIN
SET @CurrentPosition = @CurrentPosition + 2
END
ELSE
BEGIN
SET @CurrentPosition = @CurrentPosition + 1
END
SET @MP1 = @MP1 + 'T'
SET @MP2 = @MP2 + 'T'
END
END
ELSE IF @CurrentChar = 'V'
BEGIN
IF (SUBSTRING(@Word,@CurrentPosition + 1,1) = 'V')
BEGIN
SET @CurrentPosition = @CurrentPosition + 2
END
ELSE
BEGIN
SET @CurrentPosition = @CurrentPosition + 1
END
SET @MP1 = @MP1 + 'F'
SET @MP2 = @MP2 + 'F'
END
ELSE IF @CurrentChar = 'W'
BEGIN
--can also be in middle of word
IF (dbo.fnStringAt(@CurrentPosition, @Word, 'WR')=1)
BEGIN
SET @MP1 = @MP1 + 'R'
SET @MP2 = @MP2 + 'R'
SET @CurrentPosition = @CurrentPosition + 2
END
ELSE IF ((@CurrentPosition = 1)
AND ((dbo.fnIsVowel(SUBSTRING(@Word,@CurrentPosition + 1,1))=1)
OR (dbo.fnStringAt(@CurrentPosition, @Word, 'WH')=1)))
BEGIN
--Wasserman should match Vasserman
IF (dbo.fnIsVowel(SUBSTRING(@Word,@CurrentPosition + 1,1))=1)
BEGIN
SET @MP1 = @MP1 + 'A'
SET @MP2 = @MP2 + 'F'
END
ELSE
BEGIN
--need Uomo to match Womo
SET @MP1 = @MP1 + 'A'
SET @MP2 = @MP2 + 'A'
END
SET @CurrentPosition = @CurrentPosition + 1
END
--Arnow should match Arnoff
ELSE IF (((@CurrentPosition = @WordLength) AND
(dbo.fnIsVowel(SUBSTRING(@Word,@CurrentPosition - 1,1))=1))
OR (dbo.fnStringAt((@CurrentPosition - 1), @Word,
'EWSKI,EWSKY,OWSKI,OWSKY')=1)
OR (dbo.fnStringAt(1, @Word, 'SCH')=1))
BEGIN
SET @MP1 = @MP1 + ''
SET @MP2 = @MP2 + 'F'
SET @CurrentPosition = @CurrentPosition + 1
END
--polish e.g. 'filipowicz'
ELSE IF (dbo.fnStringAt(@CurrentPosition, @Word, 'WICZ,WITZ')=1)
BEGIN
SET @MP1 = @MP1 + 'TS'
SET @MP2 = @MP2 + 'FX'
SET @CurrentPosition = @CurrentPosition + 4
END
-- skip it
ELSE
BEGIN
SET @CurrentPosition = @CurrentPosition + 1
END
END
ELSE IF @CurrentChar = 'X'
BEGIN
--french e.g. breaux
IF (NOT((@CurrentPosition = @WordLength)
AND ((dbo.fnStringAt((@CurrentPosition - 3), @Word, 'IAU,EAU')=1)
OR (dbo.fnStringAt((@CurrentPosition - 2), @Word,
'AU,OU')=1))) )
BEGIN
SET @MP1 = @MP1 + 'KS'
SET @MP2 = @MP2 + 'KS'
END
IF (dbo.fnStringAt((@CurrentPosition + 1), @Word, 'C,X')=1)
BEGIN
SET @CurrentPosition = @CurrentPosition + 2
END
ELSE
BEGIN
SET @CurrentPosition = @CurrentPosition + 1
END
END
ELSE IF @CurrentChar = 'Z'
BEGIN
--chinese pinyin e.g. 'zhao'
IF (SUBSTRING(@Word,@CurrentPosition + 1,1) = 'H')
BEGIN
SET @MP1 = @MP1 + 'J'
SET @MP2 = @MP2 + 'J'
SET @CurrentPosition = @CurrentPosition + 2
END
ELSE
BEGIN
IF ((dbo.fnStringAt((@CurrentPosition + 1), @Word, 'ZO,ZI,ZA')=1)
OR ((dbo.fnSlavoGermanic(@Word)=1) AND ((@CurrentPosition >
1) AND SUBSTRING(@Word,@CurrentPosition - 1,1) <> 'T')))
BEGIN
SET @MP1 = @MP1 + 'S'
SET @MP2 = @MP2 + 'TS'
END
ELSE
BEGIN
SET @MP1 = @MP1 + 'S'
SET @MP2 = @MP2 + 'S'
END
IF (SUBSTRING(@Word,@CurrentPosition + 1,1) = 'Z')
BEGIN
SET @CurrentPosition = @CurrentPosition + 2
END
ELSE
BEGIN
SET @CurrentPosition = @CurrentPosition + 1
END
END
END
ELSE
BEGIN
SET @CurrentPosition = @CurrentPosition + 1
END
END
--only give back 4 char metaphone
IF (LEN(@MP1) > 4)
BEGIN
SET @MP1 = LEFT(@MP1, 4)
END
IF (LEN(@MP2) > 4)
BEGIN
SET @MP2 = LEFT(@MP2, 4)
END
IF @MP2 = @MP1
BEGIN
SET @MP2 = ''
END
INSERT @DMP(Metaphone1,Metaphone2) VALUES( @MP1, @MP2 )
RETURN
END
GO;
------------------------------------------------------------------------
IF OBJECT_ID('fnDoubleMetaphoneScalar') IS NOT NULL BEGIN DROP FUNCTION
fnDoubleMetaphoneScalar END
GO;
CREATE FUNCTION fnDoubleMetaphoneScalar( @MetaphoneType int, @Word varchar(50) )
RETURNS char(4)
AS
BEGIN
RETURN (SELECT CASE @MetaphoneType WHEN 1 THEN Metaphone1
WHEN 2 THEN Metaphone2 END FROM fnDoubleMetaphoneTable( @Word ))
END
回答7:
You can use the SOUNDEX and related DIFFERENCE function in SQL Server to find similar names. The reference on MSDN is here.
回答8:
Regarding de-duping things your string split and match is great first cut. If there are known items about the data that can be leveraged to reduce workload and/or produce better results, it is always good to take advantage of them. Bear in mind that often for de-duping it is impossible to entirely eliminate manual work, although you can make that much easier by catching as much as you can automatically and then generating reports of your "uncertainty cases."
Regarding name matching: SOUNDEX is horrible for quality of matching and especially bad for the type of work you are trying to do as it will match things that are too far from the target. It's better to use a combination of double metaphone results and the Levenshtein distance to perform name matching. With appropriate biasing this works really well and could probably be used for a second pass after doing a cleanup on your knowns.
You may also want to consider using an SSIS package and looking into Fuzzy Lookup and Grouping transformations (http://msdn.microsoft.com/en-us/library/ms345128(SQL.90).aspx).
Using SQL Full-Text Search (http://msdn.microsoft.com/en-us/library/cc879300.aspx) is a possibility as well, but is likely not appropriate to your specific problem domain.
回答9:
Pasting RedFilter code in two parts ,so as to avoid link rot
References:
https://github.com/mb16/geocoderNet/blob/master/build/sql/doubleMetaphone.sql
Part1:
--WEB LISTING 1: Double Metaphone Script
-------------------------------------
IF OBJECT_ID('fnIsVowel') IS NOT NULL BEGIN DROP FUNCTION fnIsVowel END
GO;
CREATE FUNCTION fnIsVowel( @c char(1) )
RETURNS bit
AS
BEGIN
IF (@c = 'A') OR (@c = 'E') OR (@c = 'I') OR (@c = 'O') OR (@c = 'U') OR (@c = 'Y')
BEGIN
RETURN 1
END
--'ELSE' would worry SQL Server, it wants RETURN last in a scalar function
RETURN 0
END
GO;
-----------------------------------------------
IF OBJECT_ID('fnSlavoGermanic') IS NOT NULL BEGIN DROP FUNCTION fnSlavoGermanic
END
GO;
CREATE FUNCTION fnSlavoGermanic( @Word char(50) )
RETURNS bit
AS
BEGIN
--Catch NULL also...
IF (CHARINDEX('W',@Word) > 0) OR (CHARINDEX('K',@Word) > 0) OR
(CHARINDEX('CZ',@Word) > 0)
--'WITZ' test is in original Lawrence Philips C++ code, but appears to be a subset of the first test for 'W'
-- OR (CHARINDEX('WITZ',@Word) > 0)
BEGIN
RETURN 1
END
--ELSE
RETURN 0
END
GO;
---------------------------------------------------------------------------------------------------------------------------------
----------------------
--Lawrence Philips calls for a length argument, but this has two drawbacks:
--1. All target strings must be of the same length
--2. It presents an opportunity for subtle bugs, ie fnStringAt( 1, 7, 'Search me please', 'Search' ) returns 0 (no matter what is in the searched string)
--So I've eliminated the argument and fnStringAt checks the length of each target as it executes
--DEFAULTS suck with UDFs. Have to specify DEFAULT in caller - why bother?
IF OBJECT_ID('fnStringAtDef') IS NOT NULL BEGIN DROP FUNCTION fnStringAtDef END
GO;
CREATE FUNCTION fnStringAtDef( @Start int, @StringToSearch varchar(50),
@Target1 varchar(50),
@Target2 varchar(50) = NULL,
@Target3 varchar(50) = NULL,
@Target4 varchar(50) = NULL,
@Target5 varchar(50) = NULL,
@Target6 varchar(50) = NULL )
RETURNS bit
AS
BEGIN
IF CHARINDEX(@Target1,@StringToSearch,@Start) > 0 RETURN 1
--2 Styles, test each optional argument for NULL, nesting further tests
--or just take advantage of CHARINDEX behavior with a NULL arg (unless 65 compatibility - code check before CREATE FUNCTION?
--Style 1:
--IF @Target2 IS NOT NULL
--BEGIN
-- IF CHARINDEX(@Target2,@StringToSearch,@Start) > 0 RETURN 1
-- (etc.)
--END
--Style 2:
IF CHARINDEX(@Target2,@StringToSearch,@Start) > 0 RETURN 1
IF CHARINDEX(@Target3,@StringToSearch,@Start) > 0 RETURN 1
IF CHARINDEX(@Target4,@StringToSearch,@Start) > 0 RETURN 1
IF CHARINDEX(@Target5,@StringToSearch,@Start) > 0 RETURN 1
IF CHARINDEX(@Target6,@StringToSearch,@Start) > 0 RETURN 1
RETURN 0
END
GO;
-------------------------------------------------------------------------------------------------
IF OBJECT_ID('fnStringAt') IS NOT NULL BEGIN DROP FUNCTION fnStringAt END
GO;
CREATE FUNCTION fnStringAt( @Start int, @StringToSearch varchar(50), @TargetStrings
varchar(2000) )
RETURNS bit
AS
BEGIN
DECLARE @SingleTarget varchar(50)
DECLARE @CurrentStart int
DECLARE @CurrentLength int
--Eliminate special cases
--Trailing space is needed to check for end of word in some cases, so always append comma
--loop tests should fairly quickly ignore ',,' termination
SET @TargetStrings = @TargetStrings + ','
SET @CurrentStart = 1
--Include terminating comma so spaces don't get truncated
SET @CurrentLength = (CHARINDEX(',',@TargetStrings,@CurrentStart) -
@CurrentStart) + 1
SET @SingleTarget = SUBSTRING(@TargetStrings,@CurrentStart,@CurrentLength)
WHILE LEN(@SingleTarget) > 1
BEGIN
IF SUBSTRING(@StringToSearch,@Start,LEN(@SingleTarget)-1) =
LEFT(@SingleTarget,LEN(@SingleTarget)-1)
BEGIN
RETURN 1
END
SET @CurrentStart = (@CurrentStart + @CurrentLength)
SET @CurrentLength = (CHARINDEX(',',@TargetStrings,@CurrentStart) -
@CurrentStart) + 1
IF NOT @CurrentLength > 1 --getting trailing comma
BEGIN
BREAK
END
SET @SingleTarget =
SUBSTRING(@TargetStrings,@CurrentStart,@CurrentLength)
END
RETURN 0
END
GO;
------------------------------------------------------------------------
IF OBJECT_ID('fnDoubleMetaphoneTable') IS NOT NULL BEGIN DROP FUNCTION
fnDoubleMetaphoneTable END
GO;
CREATE FUNCTION fnDoubleMetaphoneTable( @Word varchar(50) )
RETURNS @DMP TABLE ( Metaphone1 char(4), Metaphone2 char(4) )
AS
BEGIN
DECLARE @MP1 varchar(4), @MP2 varchar(4)
SET @MP1 = ''
SET @MP2 = ''
DECLARE @CurrentPosition int, @WordLength int, @CurrentChar char(1)
SET @CurrentPosition = 1
SET @WordLength = LEN(@Word)
IF @WordLength < 1
BEGIN
RETURN
END
--ensure case insensitivity
SET @Word = UPPER(@Word)
IF dbo.fnStringAt(1, @Word, 'GN,KN,PN,WR,PS') = 1
BEGIN
SET @CurrentPosition = @CurrentPosition + 1
END
IF 'X' = LEFT(@Word,1)
BEGIN
SET @MP1 = @MP1 + 'S'
SET @MP2 = @MP2 + 'S'
SET @CurrentPosition = @CurrentPosition + 1
END
WHILE (4 > LEN(RTRIM(@MP1))) OR (4 > LEN(RTRIM(@MP2)))
BEGIN
IF @CurrentPosition > @WordLength
BEGIN
BREAK
END
SET @CurrentChar = SUBSTRING(@Word,@CurrentPosition,1)
IF @CurrentChar IN('A','E','I','O','U','Y')
BEGIN
IF @CurrentPosition = 1
BEGIN
SET @MP1 = @MP1 + 'A'
SET @MP2 = @MP2 + 'A'
END
SET @CurrentPosition = @CurrentPosition + 1
END
ELSE IF @CurrentChar = 'B'
BEGIN
SET @MP1 = @MP1 + 'P'
SET @MP2 = @MP2 + 'P'
IF 'B' = SUBSTRING(@Word,@CurrentPosition + 1,1)
BEGIN
SET @CurrentPosition = @CurrentPosition + 2
END
ELSE
BEGIN
SET @CurrentPosition = @CurrentPosition + 1
END
END
ELSE IF @CurrentChar = 'Ç'
BEGIN
SET @MP1 = @MP1 + 'S'
SET @MP2 = @MP2 + 'S'
SET @CurrentPosition = @CurrentPosition + 1
END
ELSE IF @CurrentChar = 'C'
BEGIN
--various germanic
IF (@CurrentPosition > 2)
AND (dbo.fnIsVowel(SUBSTRING(@Word,@CurrentPosition-2,1))=0)
AND (dbo.fnStringAt(@CurrentPosition-1,@Word,'ACH') = 1)
AND ((SUBSTRING(@Word,@CurrentPosition+2,1) <> 'I')
AND ((SUBSTRING(@Word,@CurrentPosition+2,1) <> 'E') OR
(dbo.fnStringAt(@CurrentPosition-2,@Word,'BACHER,MACHER')=1)))
BEGIN
SET @MP1 = @MP1 + 'K'
SET @MP2 = @MP2 + 'K'
SET @CurrentPosition = @CurrentPosition + 2
END
-- 'caesar'
ELSE IF (@CurrentPosition = 1) AND
(dbo.fnStringAt(@CurrentPosition,@Word,'CAESAR') = 1)
BEGIN
SET @MP1 = @MP1 + 'S'
SET @MP2 = @MP2 + 'S'
SET @CurrentPosition = @CurrentPosition + 2
END
-- 'chianti'
ELSE IF dbo.fnStringAt(@CurrentPosition,@Word,'CHIA') = 1
BEGIN
SET @MP1 = @MP1 + 'K'
SET @MP2 = @MP2 + 'K'
SET @CurrentPosition = @CurrentPosition + 2
END
ELSE IF dbo.fnStringAt(@CurrentPosition,@Word,'CH') = 1
BEGIN
-- Find 'michael'
IF (@CurrentPosition > 1) AND
(dbo.fnStringAt(@CurrentPosition,@Word,'CHAE') = 1)
BEGIN
--First instance of alternate encoding
SET @MP1 = @MP1 + 'K'
SET @MP2 = @MP2 + 'X'
SET @CurrentPosition = @CurrentPosition + 2
END
--greek roots e.g. 'chemistry', 'chorus'
ELSE IF (@CurrentPosition = 1) AND (dbo.fnStringAt(2, @Word,
'HARAC,HARIS,HOR,HYM,HIA,HEM') = 1) AND (dbo.fnStringAt(1,@Word,'CHORE') = 0)
BEGIN
SET @MP1 = @MP1 + 'K'
SET @MP2 = @MP2 + 'K'
SET @CurrentPosition = @CurrentPosition + 2
END
--germanic, greek, or otherwise 'ch' for 'kh' sound
ELSE IF ((dbo.fnStringAt(1,@Word,'VAN ,VON ,SCH')=1) OR
(dbo.fnStringAt(@CurrentPosition-
2,@Word,'ORCHES,ARCHIT,ORCHID')=1) OR
(dbo.fnStringAt(@CurrentPosition+2,@Word,'T,S')=1) OR
(((dbo.fnStringAt(@CurrentPosition-1,@Word,'A,O,U,E')=1)
OR
(@CurrentPosition = 1))
AND
(dbo.fnStringAt(@CurrentPosition+2,@Word,'L,R,N,M,B,H,F,V,W, ')=1)))
BEGIN
SET @MP1 = @MP1 + 'K'
SET @MP2 = @MP2 + 'K'
SET @CurrentPosition = @CurrentPosition + 2
END
ELSE
BEGIN
--is this a given?
IF (@CurrentPosition > 1)
BEGIN
IF (dbo.fnStringAt(1,@Word,'MC') = 1)
BEGIN
--eg McHugh
SET @MP1 = @MP1 + 'K'
SET @MP2 = @MP2 + 'K'
END
ELSE
BEGIN
--Alternate encoding
SET @MP1 = @MP1 + 'X'
SET @MP2 = @MP2 + 'K'
END
END
ELSE
BEGIN
SET @MP1 = @MP1 + 'X'
SET @MP2 = @MP2 + 'X'
END
SET @CurrentPosition = @CurrentPosition + 2
END
END
--e.g, 'czerny'
ELSE IF (dbo.fnStringAt(@CurrentPosition,@Word,'CZ')=1) AND
(dbo.fnStringAt((@CurrentPosition - 2),@Word,'WICZ')=0)
BEGIN
SET @MP1 = @MP1 + 'S'
SET @MP2 = @MP2 + 'X'
SET @CurrentPosition = @CurrentPosition + 2
END
--e.g., 'focaccia'
ELSE IF(dbo.fnStringAt((@CurrentPosition + 1),@Word,'CIA')=1)
BEGIN
SET @MP1 = @MP1 + 'X'
SET @MP2 = @MP2 + 'X'
SET @CurrentPosition = @CurrentPosition + 3
END
--double 'C', but not if e.g. 'McClellan'
ELSE IF(dbo.fnStringAt(@CurrentPosition,@Word,'CC')=1) AND NOT
((@CurrentPosition = 2) AND (LEFT(@Word,1) = 'M'))
--'bellocchio' but not 'bacchus'
IF (dbo.fnStringAt((@CurrentPosition + 2),@Word,'I,E,H')=1) AND
(dbo.fnStringAt((@CurrentPosition + 2),@Word,'HU')=0)
BEGIN
--'accident', 'accede' 'succeed'
IF (((@CurrentPosition = 2) AND
(SUBSTRING(@Word,@CurrentPosition - 1,1) = 'A'))
OR (dbo.fnStringAt((@CurrentPosition -
1),@Word,'UCCEE,UCCES')=1))
BEGIN
SET @MP1 = @MP1 + 'KS'
SET @MP2 = @MP2 + 'KS'
END
--'bacci', 'bertucci', other italian
ELSE
BEGIN
SET @MP1 = @MP1 + 'X'
SET @MP2 = @MP2 + 'X'
END
SET @CurrentPosition = @CurrentPosition + 3
END
--Pierce's rule
ELSE
BEGIN
SET @MP1 = @MP1 + 'K'
SET @MP2 = @MP2 + 'K'
SET @CurrentPosition = @CurrentPosition + 2
END
ELSE IF (dbo.fnStringAt(@CurrentPosition,@Word,'CK,CG,CQ')=1)
BEGIN
SET @MP1 = @MP1 + 'K'
SET @MP2 = @MP2 + 'K'
SET @CurrentPosition = @CurrentPosition + 2
END
ELSE IF (dbo.fnStringAt(@CurrentPosition,@Word,'CI,CE,CY')=1)
BEGIN
--italian vs. english
IF (dbo.fnStringAt(@CurrentPosition,@Word,'CIO,CIE,CIA')=1)
BEGIN
SET @MP1 = @MP1 + 'S'
SET @MP2 = @MP2 + 'X'
END
ELSE
BEGIN
SET @MP1 = @MP1 + 'S'
SET @MP2 = @MP2 + 'S'
END
SET @CurrentPosition = @CurrentPosition + 2
END
ELSE
BEGIN
SET @MP1 = @MP1 + 'K'
SET @MP2 = @MP2 + 'K'
--name sent in 'mac caffrey', 'mac gregor
IF (dbo.fnStringAt((@CurrentPosition + 1),@Word,' C, Q, G')=1)
BEGIN
SET @CurrentPosition = @CurrentPosition + 3
END
ELSE
BEGIN
IF (dbo.fnStringAt((@CurrentPosition + 1),@Word,'C,K,Q')=1)
AND (dbo.fnStringAt((@CurrentPosition + 1), 2, 'CE,CI')=0)
BEGIN
SET @CurrentPosition = @CurrentPosition + 2
END
ELSE
BEGIN
SET @CurrentPosition = @CurrentPosition + 1
END
END
END
END
ELSE IF @CurrentChar = 'D'
BEGIN
IF (dbo.fnStringAt(@CurrentPosition, @Word, 'DG')=1)
BEGIN
IF (dbo.fnStringAt((@CurrentPosition + 2),@Word,'I,E,Y')=1)
BEGIN
--e.g. 'edge'
SET @MP1 = @MP1 + 'J'
SET @MP2 = @MP2 + 'J'
SET @CurrentPosition = @CurrentPosition + 3
END
ELSE
BEGIN
--e.g. 'edgar'
SET @MP1 = @MP1 + 'TK'
SET @MP2 = @MP2 + 'TK'
SET @CurrentPosition = @CurrentPosition + 2
END
END
ELSE IF (dbo.fnStringAt(@CurrentPosition,@Word,'DT,DD')=1)
BEGIN
SET @MP1 = @MP1 + 'T'
SET @MP2 = @MP2 + 'T'
SET @CurrentPosition = @CurrentPosition + 2
END
ELSE
BEGIN
SET @MP1 = @MP1 + 'T'
SET @MP2 = @MP2 + 'T'
SET @CurrentPosition = @CurrentPosition + 1
END
END
ELSE IF @CurrentChar = 'F'
BEGIN
IF (SUBSTRING(@Word,@CurrentPosition + 1,1) = 'F')
BEGIN
SET @CurrentPosition = @CurrentPosition + 2
END
ELSE
BEGIN
SET @CurrentPosition = @CurrentPosition + 1
END
SET @MP1 = @MP1 + 'F'
SET @MP2 = @MP2 + 'F'
END
ELSE IF @CurrentChar = 'G'
BEGIN
IF (SUBSTRING(@Word,@CurrentPosition + 1,1) = 'H')
BEGIN
IF (@CurrentPosition > 1) AND
(dbo.fnIsVowel(SUBSTRING(@Word,@CurrentPosition - 1,1)) = 0)
BEGIN
SET @MP1 = @MP1 + 'K'
SET @MP2 = @MP2 + 'K'
SET @CurrentPosition = @CurrentPosition + 2
END
--'ghislane', ghiradelli
ELSE IF (@CurrentPosition = 1)
BEGIN
IF (SUBSTRING(@Word,@CurrentPosition + 2,1) = 'I')
BEGIN
SET @MP1 = @MP1 + 'J'
SET @MP2 = @MP2 + 'J'
END
ELSE
BEGIN
SET @MP1 = @MP1 + 'K'
SET @MP2 = @MP2 + 'K'
END
SET @CurrentPosition = @CurrentPosition + 2
END
--Parker's rule (with some further refinements) - e.g., 'hugh'
ELSE IF (((@CurrentPosition > 2) AND (dbo.fnStringAt((@CurrentPosition
- 2),@Word,'B,H,D')=1) )
--e.g., 'bough'
OR ((@CurrentPosition > 3) AND (dbo.fnStringAt((@CurrentPosition
- 3),@Word,'B,H,D')=1) )
--e.g., 'broughton'
OR ((@CurrentPosition > 4) AND (dbo.fnStringAt((@CurrentPosition
- 4),@Word,'B,H')=1) ) )
BEGIN
SET @CurrentPosition = @CurrentPosition + 2
END
ELSE
BEGIN
--e.g., 'laugh', 'McLaughlin', 'cough', 'gough', 'rough', 'tough'
IF ((@CurrentPosition > 3)
AND (SUBSTRING(@Word,@CurrentPosition - 1,1) = 'U')
AND (dbo.fnStringAt((@CurrentPosition -
3),@Word,'C,G,L,R,T')=1) )
BEGIN
SET @MP1 = @MP1 + 'F'
SET @MP2 = @MP2 + 'F'
END
ELSE
BEGIN
IF ((@CurrentPosition > 1) AND
SUBSTRING(@Word,@CurrentPosition - 1,1) <> 'I')
BEGIN
SET @MP1 = @MP1 + 'K'
SET @MP2 = @MP2 + 'K'
END
END
SET @CurrentPosition = @CurrentPosition + 2
END
END
ELSE IF (SUBSTRING(@Word,@CurrentPosition + 1,1) = 'N')
BEGIN
IF ((@CurrentPosition = 2) AND (dbo.fnIsVowel(LEFT(@Word,1))=1) AND
(dbo.fnSlavoGermanic(@Word)=0))
BEGIN
SET @MP1 = @MP1 + 'KN'
SET @MP2 = @MP2 + 'N'
END
ELSE
BEGIN
--not e.g. 'cagney'
IF ((dbo.fnStringAt((@CurrentPosition + 2),@Word,'EY')=0)
AND (SUBSTRING(@Word,@CurrentPosition + 1,1) <>
'Y') AND (dbo.fnSlavoGermanic(@Word)=0))
回答10:
do it this way
create table person(
personid int identity(1,1) primary key,
firstname varchar(20),
lastname varchar(20),
addressindex int,
sound varchar(10)
)
and later on create a trigger
create trigger trigoninsert for dbo.person
on insert
as
declare @personid int;
select @personid=personid from inserted;
update person
set sound=soundex(firstname) where personid=@personid;
now what i can do is i can create a procedure which looks something like this
create procedure getfuzzi(@personid int)
as
declare @sound varchar(10);
set @sound=(select sound from person where personid=@personid;
select personid,firstname,lastname,addressindex from person
where sound=@sound
this will return you all the names that are nearly in match with the names provided by for a particular personid
来源：https://stackoverflow.com/questions/921978/fuzzy-matching-using-t-sql