title: Join two tables with different number of rows in MySQL
body: <p>I have two tables:</p>
  
  <pre><code>---------
  |dogs   |
  ---------
  |item_1 |
  |       |
  |       |
  |       |
  ---------
  
  ---------
  |cats   |
  ---------
  |item_1 |
  |item_2 |
  |item_3 |
  |item_4 |
  ---------
  </code></pre>
  
  <p>so I want to join the tables something like this: </p>
  
  <pre><code>------------------
  |dogs   | cats   |
  ------------------
  |item_1 | item1  |
  |NULL   | item2  |
  |NULL   | item3  |
  |NULL   | item4  |
  ------------------
  </code></pre>
  
  <p>I use a condition in the second table, but if nothing is found I still want to get that single result from the first table something like this:</p>
  
  <pre><code>------------------
  |dogs   | cats   |
  ------------------
  |item_1 | NULL   |
  ------------------
  </code></pre>
  
  <p>The tables don't have ID fields, but I can also add an ID to make a relation between the items.</p>
  
  <p>I already tried different solutions, but I can't get to keep the single result from the first table if nothing was found in the second table when using a condition (I get 0 rows), or I get repeated the item1 in the first table when I actually need Nulls.</p>