title: SQL- JOIN two column from two tables
body: <p>I need help to formulate a query. I want to select all DISTINCT colors from TABLE A and TABLE B.</p>
  
  <p>This is the wanted result from the query:</p>
  
  <pre><code>BLACK
  RED
  YELLOW
  BLUE
  </code></pre>
  
  <p>I have these tables:</p>
  
  <p>TABLE A</p>
  
  <pre><code>ID   NAME    COLOR
  5    SOCKS   BLACK
  4    SOCKS   RED
  </code></pre>
  
  <p>TABLE B </p>
  
  <pre><code>ID   NAME   COLOR 
  0    CAR    BLUE
  1    BIKE   BLUE
  5    TRUCK  YELLOW
  10   PLANE  NULL
  </code></pre>
  
  <p>I have tried:</p>
  
  <pre><code>SELECT DISTINCT A.color FROM A JOIN B ON b.color
  </code></pre>
  
  <p>But I don't get all the colors. :(</p>