Built an AI + SQL Q&A System — How to Keep High Accuracy on Complex Queries Without Gemini?

Hey,

I’m working on a Python + PostgreSQL system where:

• User query → LLM generates SQL
• Data is fetched from PostgreSQL
• LLM processes data (including calculations/derivations) to generate the final answer

Main issue: achieving high accuracy on complex, multi-parameter queries (not just simple trends), especially when the system needs to combine multiple fields and perform calculations/inference similar to Gemini.

Problems:

• Slow response
• Need a free/open-source alternative to Gemini
• Want strong reasoning + calculation capability from the model

Questions:

1. How can I improve accuracy and reasoning for complex, multi-parameter queries in this setup?
2. Which free/open-source LLMs + architectures can match Gemini-level reasoning (including calculations and derived insights)?

Tech: Python, PostgreSQL

Any suggestions or real-world approaches would really help 🙏