title: Use like '%' and match NULL values with NUMBER columns
body: <p><a href="https://stackoverflow.com/questions/3924400/like-does-not-accept-null-value">This question</a> is almost exactly like mine but none of the answers work with my case. </p>
  
  <p>If it was my question I'd slightly edit it to make it a different question. This question is thus different from the linked one.</p>
  
  <p>Here's the problem: I want a way to match any non-null value (<code>'%'</code>) AND null values.</p>
  
  <p>The thing is:</p>
  
  <ul>
  <li><p>I'm using oracle so I can't use <code>IsNull</code></p></li>
  <li><p>Some columns are <code>NUMBER</code>s, which means I can't use <code>COALESCE(column, ' ')</code>. (<em>ORA-00932: inconsistent datatypes: expected NUMBER got CHAR</em>). However, <code>like '%'</code> and <code>like '2118'</code> do work on NUMBER columns.</p></li>
  </ul>
  
  <p>None of the answers apply to this problem because you can't make a null into an empty string when the column is a NUMBER.</p>
  
  <p>How could I do to achieve this?</p>
  
  <hr>
  
  <p>Some context:</p>
  
  <p>My procedure takes a lot of parameters, and does a select with all of them. They can all have a value or be null, so if they're null they're replaced with <code>'%'</code>.</p>
  
  <p>That way, the procedure does :</p>
  
  <pre><code>where t.col1 like param1
  and t.col2 like param2
  ...
  </code></pre>
  
  <p>Most of the times, only one or two parameters is not null. For the others parameters, the procedure needs to match on every row.</p>
  
  <p>But when the value is null, <code>like '%'</code> doesn't match the row. I'm looking for a way to match anything when param x is empty (so <code>paramx = '%'</code>)</p>