change sql endpoint

main.py

@@ -8,6 +8,7 @@ from llama_index.core.indices.struct_store import NLSQLTableQueryEngine
 import os
 from huggingface_hub import hf_hub_download
 from models import SQL
+import json
 
 app = FastAPI()
 
@@ -36,7 +37,7 @@ async def query_database(query_data: SQL):
     global query_file_path
     conn = duckdb.connect(query_file_path,read_only=True)
     df = conn.execute(query_data.query).fetch_df()
-    return JSONResponse(df.to_json(orient = "records"))
+    return JSONResponse(json.loads(df.to_json(orient = "records")))
 
 # @app.post("/llm")
 # async def llm(prompt: str):