Database question /answer with link

We have a community app with groups and would like to build a search function where users can ask: when is the next event, give me the messages posted by Erik, where can I find …

The information is stored in a table: post-test, posted-by etc.

We do not want to use OpenAI or any external apis. Is something like llama index too powerful or are there other solutions for this? And we want to receive the postId to direct the use to the post