I have a hard time to use ref in knex - because no matter what I do it returns ref is not a function.

knex.js-File

const database = knex({
    client: "pg",
    connection: connectionString,
    pool: {
        min: 2,
        max: 10,
    },
    debug: isDevelopment,
}).withSchema("appschema");

module.exports = database;

Example 1:

const database = require("../knex.js");

async function getResults() {
   const result = await database.from("table").select(database.ref("id").as("table_id"); <- ref not a function
}

Example 2:

const database = require("../knex.js");
const knex = require("knex");

async function getResults() {
   const result = await database.from("table").select(knex.ref("id").as("table_id"); <- ref not a function
}

Example 3:

const database = require("../knex.js");
const Knex = require("knex");

async function getResults() {
   const result = await database.from("table").select(Knex.ref("id").as("table_id"); <- ref not a function
}

I would expect, at least from the documentation and some examples in the web, that it should be used like the first example.

What am I doing wrong here?