title: Select objects with child objects that have both null and non-null attributes
body: <p>Say I have a table that links a parent object with multiple child objects and has columns for certain attributes of the child object. Take this simplified example below:</p>
  
  <pre><code>product_id  sku_id  size_desc  color_column_that_doesnt_matter
  123         456     (null)     black
  123         457     (null)     red
  123         458     (null)     grey
  124         567     large      green
  124         568     medium     green
  124         569     small      green
  125         678     (null)     blue
  125         679     5x5        yellow
  </code></pre>
  
  <p>Notice that Product 123 and 124 have products that all have either a null for the size description or a value for the size description. <em>Product 125 is different though</em> - It has at least one sku w/ a null size_desc and at least one one sku that has a non-null value for size_desc. </p>
  
  <p>Say there are potentially very many products like Product 125 - I want them all. How would I filter this data via a select…where statement to return all products and all skus that have this mix of null and non-null values for size_desc?</p>
  
  <p>SQL flavor is Oracle 11</p>