📝 Improve DuckDB documentation

lib/ayesql/runner/duckdb.ex

@@ -57,6 +57,64 @@ if Code.ensure_loaded?(Duckdbex) do
     iex> MyQueries.get_user([id: id], conn: connection)
     {:ok, ...}
     ```
+
+    ## Example
+
+    Given the following AyeSQL file:
+
+    ```sql
+    -- name: get_player_by_last_name
+    -- docs: Get players by their last name
+    SELECT *
+    FROM atp
+    WHERE name_last = :last_name
+    ```
+
+    And the following AyeSQL module:
+
+    ```elixir
+    defmodule ATP do
+      use AyeSQL,
+        runner: AyeSQL.Runner.Duckdbex
+
+      defqueries "./atp.sql"
+    end
+    ```
+
+    Then we can query a CSV file as follows:
+
+    ```elixir
+    # Open a DuckDB connection
+    {:ok, db} = Duckdbex.open()
+    {:ok, conn} = Duckdbex.connection(db)
+
+    # Fetch a remote CSV and copy its contents to the table `atp`
+    url = "https://raw.githubusercontent.com/duckdb-in-action/examples/refs/heads/main/ch05/atp/atp_players.csv"
+    {:ok, _res} = Duckdbex.query(conn, "INSTALL httpfs")
+    {:ok, _res} = Duckdbex.query(conn, "LOAD httpfs")
+    {:ok, _res} = Duckdbex.query(conn, "CREATE OR REPLACE TABLE atp AS FROM '\#{url}'")
+
+    # Run our query to find a player by last name
+    ATP.get_player_by_last_name([last_name: "Federer"], conn: conn)
+    ```
+
+    This should get the following result:
+
+    ```elixir
+    {:ok,
+     [
+       %{
+         player_id: 103819,
+         name_first: "Roger",
+         name_last: "Federer",
+         hand: "R",
+         dob: "19810808",
+         ioc: "SUI",
+         height: 185,
+         wikidata_id: "Q1426"
+       }
+     ]}
+    ```
     """
     use AyeSQL.Runner
 

mix.exs

@@ -134,7 +134,8 @@ defmodule AyeSQL.MixProject do
       "AyeSQL runners": [
         AyeSQL.Runner,
         AyeSQL.Runner.Ecto,
-        AyeSQL.Runner.Postgrex
+        AyeSQL.Runner.Postgrex,
+        AyeSQL.Runner.Duckdbex
       ]
     ]
   end