How Can I Prioritize Fields in MySQL Fulltext Search for Enhanced Relevance?

Prioritizing Fields in MySQL Fulltext Search for Enhanced Relevance

Suppose you encounter a situation where you have two columns, "keywords" and "content," in a table and an underlying fulltext index spanning both columns. However, you wish to give rows containing a specific term in the "keywords" column higher relevance than those containing it in the "content" column.

To accomplish this task within the context of using the "match against" syntax, you can implement a multi-faceted approach:

1. Create Multiple Fulltext Indexes:
   Establish three fulltext indexes:

   • One on the "keywords" column alone
   • One on the "content" column alone
   • One on both the "keywords" and "content" columns

2. Leverage Weighted Relevance Calculation:
   In your query, retrieve the relevance scores for both "keywords" and "content" matches separately. Then, combine these scores using weighted addition, attributing a higher weight to the "keywords" relevance:

   SELECT id, keyword, content,
   MATCH (keyword) AGAINST ('watermelon') AS rel1,
   MATCH (content) AGAINST ('watermelon') AS rel2
   FROM table
   WHERE MATCH (keyword,content) AGAINST ('watermelon')
   ORDER BY (rel1*weight_factor)+(rel2) DESC

3. Control Recall with the Combined Index:
   While the calculation above determines the relevance, it's essential to separate index usage for search and relevance. Utilize the index on both "keywords" and "content" to control recall, ensuring that relevant rows are returned in the search results.

This approach allows you to prioritize the importance of the "keywords" column for determining document relevance in your MySQL fulltext search queries. The weighting factor in the calculation enables you to fine-tune the precedence of matching terms in the desired column.

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