通过在字符串中出现一组关键字来对sql结果进行排序 [英] Order sql result by occurrence of a set of keywords in a string

问题描述

对于每行，我想将每个描述的相关性与未定义数量的关键字进行比较.我知道"THEN +1"无效，但是我想得出这个结果(...为每个存在的关键字增加一个数字(每行从0开始)

For each rows, I want to get the relevance of each description compared to an undefined number of keywords. I know that "THEN +1" does not work, but I would like to come to this result (...to have a number (starting from 0 each rows) that is incremented for each keyword present)

SELECT *,
    (CASE description LIKE '%keyword1%' THEN +1 
          description LIKE '%keyword2%' THEN +1
          (...) 
          ELSE 0
    END) as relevance_description
FROM (...)
ORDER BY relevance_description DESC

因此，如果描述包含"keyword1"和"keyword2"，则此行的relevance_description应该为2.

So, if a description contains "keyword1" and "keyword2", relevance_description should be 2 for this row.

推荐答案

您可以使用单独的子句执行此操作，并将它们添加在一起:

You can do this with separate clauses, and add them together:

SELECT *,
       ((CASE description LIKE '%keyword1%' THEN 1 else 0 end) +
        (case description LIKE '%keyword2%' THEN 1 else 0 end) +
        . . .
       ) as relevance_description
FROM (...)
ORDER BY relevance_description DESC;

在某些数据库中，布尔值被视为整数，因此您可以编写:

In some databases, booleans are treated as integers, so you could just write:

SELECT *,
       ((description LIKE '%keyword1%') +
        (description LIKE '%keyword2%') +
        . . .
       ) as relevance_description
FROM (...)
ORDER BY relevance_description DESC;

这篇关于通过在字符串中出现一组关键字来对sql结果进行排序的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！