title: why mysql returns some rows when it should return null?
body: <p>here is structure of <code>myTable</code></p>
  
  <pre><code>----------------
  |id|info1|info2|
  ----------------
  |0 |abcde|fghij|
  |1 |qwert|yuopa|
  ----------------
  </code></pre>
  
  <p>here is the query I call : </p>
  
  <pre><code>SELECT * FROM `myTable` WHERE `id` = 'a'
  </code></pre>
  
  <p>and it returns the first row which is</p>
  
  <pre><code>|0 |abcde|fghij|
  </code></pre>
  
  <p>what is happening? normally <code>id</code> is an integer but, by mistake I typed it as a string but I still got a result.</p>