SQL Server 2008中列中出现的所有单词的单词计数 [英] Word count for all the words appearing in a column in SQL Server 2008

问题描述

我有一个名为'ticket_diary_comment'的表，其中有一个名为'comment_text'的列.此列中填充了文本数据.我想知道整个专栏中出现的所有单词的出现频率.例如:

I have a table called 'ticket_diary_comment' with a column called 'comment_text'. This column is populated with text data. I would like to get the frequency of all the words occurring in this entire column. Ex:

Comment_Text
I am a good guy
I am a bad guy
I am not a guy

我想要什么:

Word    Frequency
I       3
good    1
bad     1
not     1
guy     3

请注意，我还删除了输出中的停用词.我知道计算特定单词的频率并不困难，但我正在寻找一种方法，可以计算出出现在停用词中的所有单词.

Notice that I have also removed the stop words in the output. I know calculating the frequency of a particular word is not difficult but I am looking for something that counts all the words appearing in a column removing the stop words.

在此问题上的任何帮助，我将不胜感激. 我还要提及的是，我必须在大型数据集(大约1 TB)上应用此查询，因此性能令人担忧.

I would appreciate any kind of help on this issue. I would also like to mention that I have to apply this query on a big-ish dataset (about 1 TB), so performance is a concern.

推荐答案

我将使用表值函数拆分字符串，然后在查询中将它们分组.像这样:

I would use a table valued function to split the strings, and then group them in a query. Something like this:

SELECT item, count(1)
FROM ticket_diary_comment 
    CROSS APPLY dbo.fn_SplitString(comment_text, ' ')
GROUP BY item

以及fn_SplitString的定义:

CREATE FUNCTION [dbo].[fn_SplitString]   
(   
    @String VARCHAR(8000),   
    @Delimiter VARCHAR(255)   
)   
RETURNS   
@Results TABLE   
(   
    ID INT IDENTITY(1, 1),   
    Item VARCHAR(8000)   
)   
AS   
BEGIN   
INSERT INTO @Results (Item)   
SELECT SUBSTRING(@String+@Delimiter, num,   
    CHARINDEX(@Delimiter, @String+@Delimiter, num) - num)   
FROM Numbers   
WHERE num <= LEN(REPLACE(@String,' ','|'))   
AND SUBSTRING(@Delimiter + @String,   
            num,   
            LEN(REPLACE(@delimiter,' ','|'))) = @Delimiter   
ORDER BY num RETURN   
END   

此功能需要数字表，其中基本上只是CREATE TABLE Numbers(Num int)，并且包含从1到10,000(或更多/更少，取决于需要)的所有数字.如果您的数据库中已经有一个数字表，则可以用该表/列替换现有的表.

This function requires a numbers table, which is basically just CREATE TABLE Numbers(Num int) and contains all the numbers from 1 to 10,000 (or more/less depending on needs). If you already have a numbers table in your DB you can substitute that table/column for what you already have.

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