title: Compare column values in mysql tables
body: <p>I have two tables, table A and table B. I need to compare their columns to get values of one table that are not in other table.</p>
  
  <ul>
  <li>Table A columns : ID,table_id(key reference to table B),data</li>
  <li>Table B columns : ID(primary key,references to table A),x,y</li>
  </ul>
  
  <p>I need to get values from A.table_id that are not equal to B.ID</p>
  
  <p>A.table_id values = 3,3,2
  B.ID values = 1,2,3</p>
  
  <p>I need to get value 1.</p>