title: Case When syntax expression in jooq
body: <p>I am trying to reproduce this MySQL query in jooq</p>
  
  <pre class="lang-sql prettyprint-override"><code>select case     
  when year(d.date) - p.birth_year &lt; 5 then '&lt;5' 
  else '5+'
  end as age
  from partners p join departure d on d.id = p.id
  </code></pre>
  
  <p>to</p>
  
  <pre class="lang-java prettyprint-override"><code>this.schema().select(
  DSL.decode().value(dateDiff(p.BIRTHDATE , date(d.DATE)))
     .when(greaterThan(5), "above 5")
     .when(lessThan(5), "under 5")
     .otherwise("unknown").as("age"),
     .from(p)
     .join(d).on(d.ID.eq(p.ID))
  </code></pre>