Query that returns parent items with no children
<p>I have a table that looks like this:</p>

<p><a href="https://i.stack.imgur.com/3RLm4.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/3RLm4.png" alt="enter image description here"></a></p>

<p>It has products. Some are related to a parent product by a "Parent ID".</p>

<p>I need a query that will only select parent products that don't have any children related to it. Such as "Product-4".</p>

<p>Can anyone help me with this? It seems quite an easy solution.</p>