Query search in SQL vs vector store



I am building an assistant that has a vector store with data about products. It works quite well for basic questions that are likely to be part of the documents in the store.
But I struggle with user queries such as “give me a product that is heavier than product X” (from previous conversation). I am not sure how to implement this functionality and more importantly how to distinguish between plain query to vector store and this type of search.

My idea is to use a function calling and bind it with a SQL database, but I feel I am overcomplicating things.

Can I ask for suggestions and/or common practice in this case?

Thanks. J