title: Join query with null values
body: <p>I have this query</p>
  
  <pre><code>SELECT * FROM orders, products, suppliers 
  WHERE product_id=products.id 
    AND `geleverd` = 1  
    AND supplier_id=suppliers.id
  </code></pre>
  
  <p>It works fine except that when the suppliers_id is NULL it is not picking those up. I need that so when a supplier is filled it should get the supplier name and when it is NULL it should also get that line because further on in the code I have <code>if supplier_id = NULL</code> place text</p>
  
  <p>This is my suppliers database:
  <a href="https://i.stack.imgur.com/OCZ4t.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/OCZ4t.png" alt="enter image description here"></a></p>
  
  <p>And this is my orders database:
  <a href="https://i.stack.imgur.com/rNAbe.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/rNAbe.png" alt="enter image description here"></a></p>
  
  <p>So my query needs to show everything where geleverd is 1 no matter if supplier_id is NULL or not</p>