title: How to use 'and' with 'on' condition of joins in knex
body: <p>I am trying to generate a query like:  </p>
  
  <pre><code>select ifnull(t1.name, ‘default’) as name
  from tab1 as t1
  left join tab2 as t2 
   on t1.id=t2.id and t2.code=“someValue”
  </code></pre>
  
  <p>I wrote this in knex:</p>
  
  <pre><code>var query = knex().from(’tab1’).join(’tab2', function() {
  
      this.on('tab1.id', '=', 'tab2.id').andOn('tab2.code', '=', 'someValue')
  }, 
  
  ‘left')
  .column([
  
  knex.raw(‘IFNULL(tab1.name, "no name") as name')
  
  ]);
  </code></pre>
  
  <p>This does not execute as it treats 'someValue' as a column.
  How can I apply 'and' condition in this case?</p>