Postgres insert or update trigger WHEN condition (old)
<p>I need write insert or update trigger, but with WHEN condition with compare OLD and NEW rows.</p>

<p>According documentation OLD is null for insert operation. How i can use OLD in WHEN condition for INSERT AND UPDATE triggers?</p>

<p>Example trigger:</p>

<pre><code>CREATE TRIGGER mytrigger
    BEFORE INSERT OR UPDATE ON "mytable"
    FOR EACH ROW 
    WHEN (NEW.score &gt; 0 AND OLD.score &lt;&gt; NEW.score)
    EXECUTE PROCEDURE mytrigger();
</code></pre>

<p>but for insert OLD is null. </p>