Enable AI-driven conversations with your PostgreSQL database using a secure and visual-free agent powered by n8n’s Model Context Protocol (MCP). This template allows users to ask multiple KPIs in a single message, returning consolidated insights — more efficient than the original Conversing with Data template.
Unlike the Conversing with Data workflow, which handles one KPI per message, this version:
💲 Estimated cost per full multi-request run: ~$0.01
This template is optimized for efficiency. Each message can return 2–4 KPIs (You can change the MaxIteration of the Agent to make it more, it is currently set up at 30 iterations) using a single Claude 3.5 Haiku session and DeepSeek-based SQL generation — balancing speed, reasoning, and affordability.
User:
“Can you show product performance, revenue trends, and top 5 customers?”
Agent:
ListTables
and GetTableSchema
get_query_and_data
📊 Product Performance
📈 Sales Trends
🧍 Customer Insights
All from one natural prompt.
Node | Purpose |
---|---|
MCP Server Trigger | Receives user queries via /mcp/... |
AI Agent + Memory | Understands and plans multi-step queries |
Think Tool | Breaks down the user’s question into structured goals |
get_query_and_data | Generates SQL securely from natural language |
ListTables, GetSchema | AI tools to explore DB safely |
Read/Insert/Update Tools | Execute structured operations (never raw SQL) |
checkdatabase Subflow | Validates SQL, formats response as clean text |
This template uses two types of models, selected for cost-performance balance and role alignment:
1. Claude 3.5 Haiku (Anthropic) – for the MCP Agent
The main conversational agent uses Claude 3.5 Haiku, ideal for MCP because it was built by Anthropic — the creators of the MCP standard. It’s fast, affordable, and performs excellently in tool-calling and reasoning tasks.
2. DeepSeek – for the SQL subworkflow
The subworkflow that turns natural language into SQL uses DeepSeek. It’s one of the most affordable and performant models available today for structured outputs like SQL, making it a perfect fit for utility logic.
✅ This setup provides top-tier reasoning + low-cost execution.
“Show me the top 5 products by units sold and revenue, total monthly sales trend, and top 5 customers by spending.”
In one message, the agent will:
Build_your_own_PostgreSQL_MCP_server_No_visuals_.json
checkdatabase.json
/mcp/...
URL from the MCP Server Trigger to connect your frontend or chatbotBuild_your_own_PostgreSQL_MCP_server_No_visuals_.json
– MCP agent logiccheckdatabase.json
– SQL generation and formatting utility workflow📝 These must be uploaded into your n8n workspace for the template to function.
Feature | Conversing with Data | This Workflow |
---|---|---|
Handles multi-KPI questions | ❌ No | ✅ Yes |
Secure query execution | ✅ Yes | ✅ Yes |
Structured response | ⚠️ JSON / raw | ✅ Clean natural language |
Cost-efficiency | ⚠️ More calls | ✅ Optimized with fewer calls |
Endpoint support | ❌ Manual interaction | ✅ MCP-ready (/mcp/... ) |
🔗 Prefer something more lightweight and cost-sensitive?
Try the original Conversing with Data template (single KPI + chart support):
Conversing with Data: Transforming Text into SQL Queries and Visual Curves
I used this version for over 3 months and only spent $0.80 total, making it a great entry point if you're just getting started or on a limited budget.
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