title: Adding two conditions to joinLeft in Slick
body: <p>This compiles:</p>
  
  <pre><code>  val table1 = TableQuery[Table1]
    val table2 = TableQuery[Table2]
  
    val query = for {
      (t1, t2) &lt;- table1 joinLeft table2 on (_.dsType === _.dsType)
    } yield (t1, t2)
  </code></pre>
  
  <p>This does <em>not</em> compile:</p>
  
  <pre><code>  val table1 = TableQuery[Table1]
    val table2 = TableQuery[Table2]
  
    val query = for {
      (t1, t2) &lt;- table1 joinLeft table2 on (_.dsType === _.dsType &amp;&amp; _.dsSk === _.dsSk)
    } yield (t1, t2)
  </code></pre>
  
  <p>What's the syntax to add two conditions to <code>joinLeft</code> ?</p>