title: Inserting records in Mysql with INSERT IGNORE and NULL values
body: <p>I have a partitioned table InnoDB with several fields. 
  I'm trying to avoid duplicates on insert.</p>
  
  <p>Let's say:</p>
  
  <pre><code>Field1 int null
  Field2 int null
  Field3 int null
  Field4 int null
  Field5 int null
  </code></pre>
  
  <p>I have created a UNIQUE index on those fields.
  I try to insert some records with NULL values and then try to reinsert them with IGNORE feature on MySql.</p>
  
  <p>Unfortunately it seems to replicated the records when using NULL values.
  If I try with zeros instead of NULL cases everything works, but I do need the nulls there.</p>
  
  <p>Any ideas?</p>