为什么或如何 FREETEXTTABLE 给出的排名值高于其他值 [英] Why or How does FREETEXTTABLE give a rank value higher than others

问题描述

有一个存储过程，在两个表上使用了两次FREETEXTTABLE，然后合并结果，返回前50个.

问题是，如果我搜索布鲁斯特的女人"，结果会返回表 A 中排名为 143 的前杜夫斯莫塔的自白"和排名为 102 的第二个布鲁斯特女性"来自表 B.

这是因为计数吗?(表A返回结果总数为2399.表B返回结果总数为3445.)

解决方案

简短的回答:

<块引用>

Freetext 排名基于 OKAPIBM25 排名公式.中的每个术语查询排名，值是总和.自由文本查询将添加通过屈折词查询词代(词干的形式原始查询词)；这些话是作为单独的术语处理，没有特殊权重或关系他们来自的词生成.从产生的同义词同义词库特征被视为独立的、同等权重的术语.

当然，可以在 Microsoft 的网站上找到更长、更复杂的答案.对于高等数学，点击此处.>

There is a store procedure that uses FREETEXTTABLE twice on two tables and then merges the results and returns the top 50.

The problem is if I do a search on "Women of Brewster", the results returns "Confession of an ex doofus motha" with a rank of 143 from table A and second "Women of Brewster Place" with a rank of 102 from table B.

Is this because of the count? (Table A return results total is 2399. Table B return results total is 3445.)

解决方案

The short answer:

Freetext ranking is based on the OKAPI BM25 ranking formula. Each term in the query is ranked, and the values are summed. Freetext queries will add words to the query via inflectional generation (stemmed forms of the original query terms); these words are treated as separate terms with no special weighting or relationship with the words from which they were generated. Synonyms generated from the Thesaurus feature are treated as separate, equally weighted terms.

The much longer, and far more complicated answer can be found on Microsoft's site, of course. For advanced mathematics, click here.

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