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我构建了一个查询来查找列的最长公共子字符串并按频率对它们进行排序。我遇到的问题是删除/分组类似的结果。

这是下面代码的 TOP 5 输出 - 请注意“I love mittens the cat”是最长、最频繁的字符串，但该代码还会找到该字符串的所有子字符串，例如“I love mittens the ca”或“I love手套 c"。

    I love Mittens the cat  3
    I love Mittens the ca   3
     love Mittens the cat   3
     love Mittens the ca    3
    I love Mittens the c    3

如果可能的话，我想删除任何与其他包含部分单词的子字符串相似的子字符串。第 3 行会很好，因为它都是完整的单词，但第 4 行和第 5 行应该被删除，因为它们与第 1 行相似。

DECLARE     @MinLength INT          = 5     --Minimum Substring Length
DECLARE     @MaxLength INT          = 50    --Maximum Substring Length
DECLARE     @Delimeter VARCHAR(5)   = ' '
DECLARE     @T TABLE
            (
                  ID INT IDENTITY
                , chvStrings VARCHAR(64)  
            )
INSERT INTO @T VALUES
            ('I like cats'),
            ('I like dogs'),
            ('cats are great'),
            ('look at that cat'),
            ('I love Mittens the cat'),
            ('I love Mittens the cat a lot'),
            ('I love Mittens the cat so much'),
            ('Dogs are okay, I guess...')

SELECT TOP 10000 
    SUBSTRING(T.chvStrings, N.Number, M.Number) AS Word,
    COUNT(M.number) AS [Count]
FROM        
    @T as T
CROSS APPLY 
    (SELECT N.Number
     FROM [master]..spt_values as N
     WHERE N.type = 'P' 
       AND N.number BETWEEN 1 AND LEN(T.chvStrings)) N
CROSS APPLY 
    (SELECT N.Number
     FROM [master]..spt_values as N
     WHERE N.type = 'P' 
       AND N.number BETWEEN @MinLength AND @MaxLength) M
WHERE       
    N.number <= LEN(t.chvStrings) - M.number + 1
    AND SUBSTRING(T.chvStrings, N.Number, M.Number) NOT LIKE '% '
    AND SUBSTRING(T.chvStrings, N.Number, M.Number) NOT LIKE '%[_]%'
    AND (SUBSTRING(T.chvStrings, N.Number,1) = @Delimeter OR  N.number = 1)
GROUP BY  
    SUBSTRING(T.chvStrings, N.Number, M.Number)                      
ORDER BY    
    COUNT(T.chvStrings) DESC,
    LEN(SUBSTRING(T.chvStrings, N.Number, M.Number)) DESC
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1 回答 1

1

我添加了几个额外的过滤器来说明子字符串 N.Number-1 不能包含字母 [a-z0-9]，同样子字符串 M.Number+1 不能是 [a-z0-9]。

这是你需要的吗。修改后的代码如下：

DECLARE     @MinLength INT          = 5     --Minimum Substring Length
DECLARE     @MaxLength INT          = 50    --Maximum Substring Length
DECLARE     @Delimeter VARCHAR(5)   = ' '
DECLARE     @T TABLE
            (
                  ID INT IDENTITY
                , chvStrings VARCHAR(64)  
            )
INSERT INTO @T VALUES
            ('I like cats'),
            ('I like dogs'),
            ('cats are great'),
            ('look at that cat'),
            ('I love Mittens the cat'),
            ('I love Mittens the cat a lot'),
            ('I love Mittens the cat so much'),
            ('Dogs are okay, I guess...')

SELECT TOP 10000 
    SUBSTRING(T.chvStrings, N.Number,  M.Number) AS Word,
    COUNT(M.number) AS [Count]
    --SUBSTRING(T.chvStrings,M.Number+1,1)
FROM        
    @T as T
CROSS APPLY 
    (SELECT N.Number
     FROM [master]..spt_values as N
     WHERE N.type = 'P' 
       AND N.number BETWEEN 1 AND LEN(T.chvStrings)) N
CROSS APPLY 
    (SELECT N.Number
     FROM [master]..spt_values as N
     WHERE N.type = 'P' 
       AND N.number BETWEEN @MinLength AND @MaxLength) M
WHERE       
    N.number <= LEN(t.chvStrings) - M.number + 1
    AND SUBSTRING(T.chvStrings, N.Number, M.Number) NOT LIKE '% '
    AND SUBSTRING(T.chvStrings, N.Number, M.Number) NOT LIKE '%[_]%'
    AND (SUBSTRING(T.chvStrings, N.Number,1) = @Delimeter OR  N.number = 1) 
    AND SUBSTRING(T.chvStrings,M.Number+1,1) NOT LIKE '%[a-z0-9]%'
    AND SUBSTRING(T.chvStrings,N.Number-1,1) NOT LIKE '%[a-z0-9]%'
GROUP BY  
    SUBSTRING(T.chvStrings, N.Number, M.Number)                      
ORDER BY    
    COUNT(T.chvStrings) DESC,
    LEN(SUBSTRING(T.chvStrings, N.Number, M.Number)) DESC
于 2016-06-09T12:05:33.953 回答