如何匹配不精确且具有不同单词顺序的字符串。通常字符串具有相似的数字模式，但单词可能的顺序不同。
例如，我会考虑匹配良好的字符串：
目标字符串：Apple 10mg/51L Tail
测试字符串：Tail 10mg/51L Apple（只是随机翻译，拼写正确）
我还会考虑以下字符串之间的良好匹配：
测试字符串：51L MissleadingLENWord ObfuscateTail 10mg Apple（如果我们用LIKE子句逐个检查每个单词，即＃34; Tail＆＃，可以在测试字符串中找到目标字符串的所有单词34;目标字符串可以在单词＆＃34; ObfuscateTail＆＃34;）中的测试字符串中找到。
我希望在函数中看到这个问题的解决方案返回百分比数字，这意味着字符串有多相似 - 零 - 字符串不同，100％两个字符串都相同。
我应该使用哪种algorytm？如果可以使用SQL Server实现它是最好的。
我可以在这里找到一些算法：Fuzzy matching using T-SQL。 领先答案中提到的 Levenshtein 距离算法是否适合于单词的混合顺序？
答案 0 :(得分：4)
只要单词被分开（空白，/或任何其他分隔符），这可以通过字符串拆分器和命中计数来完成，但是你找不到＆＃34; Tail＆ ＃34; in＆＃34; ObfuscateTail＆＃34;。您还需要一些 CamelCase解析 ......
一个相当简单的解决方法是使用所有碎片进行LIKE搜索，但这可能会带来很多 - 而且（肯定！）这不会很快......
尝试这样的事情：
DECLARE @mockupTable TABLE(ID INT IDENTITY, YourTarget VARCHAR(100));
INSERT INTO @mockupTable VALUES('51L MissleadingLENWord ObfuscateTail 10mg Apple')
,('Some other 51L with differing words');
DECLARE @search VARCHAR(100)='Apple 10mg/51L Tail';
WITH Parted AS
(
SELECT CAST('<x>' + REPLACE(REPLACE(@search,' ','/'),'/','</x><x>') + '</x>' AS XML) AS SearchFragmentsXML
)
,AllSearchWords AS
(
SELECT frgmnt.value(N'.',N'nvarchar(max)') AS Frg
FROM Parted
CROSS APPLY SearchFragmentsXML.nodes(N'/x') AS A(frgmnt)
)
SELECT ID
,COUNT(*) AS CountHits
,(SELECT COUNT(*) FROM AllSearchWords) AS CountFragments
FROM @mockupTable AS t
INNER JOIN AllSearchWords AS Frgs ON t.YourTarget LIKE '%' + Frgs.Frg + '%'
GROUP BY ID;
结果
ID CountHits CountFragments
1 4 4
2 1 4
命中次数越接近＆＃34;对于片段的数量＆＃34;越好。
DROP FUNCTION dbo.YourSearch;
GO
CREATE FUNCTION dbo.YourSearch(@SearchIn VARCHAR(MAX), @SearchFor VARCHAR(100)='Apple 10mg/51L Tail')
RETURNS FLOAT
AS
BEGIN
DECLARE @rslt DECIMAL(10,4) =
(
SELECT CAST(COUNT(*) AS FLOAT) / MAX(SearchFragmentsXML.value('count(/x[text()])','float'))
FROM
(
SELECT CAST('<x>' + REPLACE(REPLACE(@SearchFor,' ','/'),'/','</x><x>') + '</x>' AS XML) AS SearchFragmentsXML
) AS Parted
CROSS APPLY SearchFragmentsXML.nodes(N'/x') AS A(frgmnt)
WHERE @SearchIn LIKE '%' + frgmnt.value(N'text()[1]',N'nvarchar(max)') + '%'
);
RETURN @rslt;
END
GO
DECLARE @mockupTable TABLE(ID INT IDENTITY, YourTarget VARCHAR(100));
INSERT INTO @mockupTable VALUES('51L MissleadingLENWord ObfuscateTail 10mg Apple')
,('Some other 51L with differing words');
SELECT t.*
,dbo.YourSearch(t.YourTarget,'Apple 10mg/51L Tail') AS HitCoeff
FROM @mockupTable AS t;
结果
ID YourTarget HitCoeff
1 51L MissleadingLENWord ObfuscateTail 10mg Apple 1
2 Some other 51L with differing words 0,25
提示：如果您使用带有SessionID的物理表格，那么它会有很大帮助，您可以在其中填写搜索字符串的片段。然后将SessionID传递给函数并从那里抓取碎片。这至少会避免重复拆分，并且可以使用结果缓存。
答案 1 :(得分：1)
您正在寻找通常称为词组匹配的内容。
模糊的单词和单词变得凌乱。
所有方法都从拆分单词开始。
您可以使用Levenshtein distance距离，但可以使用单词中不包含字符的单词。你可以拿出这个词的哈希值。不完美但基于散列会更快。
这里常见的最佳做法是tf–idf。这是Lucene使用的。您可能认为它有点激烈但我在一个包含100万个文档的库中使用了最多100,000个单词并且它在不到1秒的时间内找到了排名匹配。再一次，你不会在这个词中变得模糊。
Cosine similarity是另一种选择。
模糊的话，你可以对Levenshtein反对每个单词并取最小的然后做一些总和。我不推荐这条路线。
答案 2 :(得分：0)
我还没有发现任何可以衡量字符串中单词混排的东西。为了换个字母，我最后使用了这个答案：https://stackoverflow.com/a/26389197/1903793
CREATE ASSEMBLY [FuzzyString]
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WITH PERMISSION_SET = SAFE
GO
CREATE FUNCTION [dbo].[Levenshtein](@S1 [nvarchar](200), @S2 [nvarchar](200))
RETURNS [float] WITH EXECUTE AS CALLER
AS
EXTERNAL NAME [FuzzyString].[StoredFunctions].[HaBoLevenshtein]
GO
示例用法：
select [dbo].[Levenshtein] ('Apple', 'Appleee')