Update app.py

app.py

@@ -69,6 +69,14 @@ def get_data_table():
 def sql_engine(query: str) -> str:
     """
     Executes an SQL query and returns formatted results.
+
+    Args:
+        query: The SQL query string to execute on the database. Must be a valid SELECT query.
+
+    Returns:
+        str: The formatted query results as a string. For single value results, returns the value.
+             For multiple rows/columns, returns newline-separated rows with comma-separated values.
+             Returns error message as string if query execution fails.
     """
     try:
         with engine.connect() as con: