title: Performance differences between equal (=) and IN with one literal value
body: <p>How does SQL engines differ when we use equal sign and IN operator have same value? Does execution time changes?</p>
  <p>1st one using equality check operator</p>
  <pre><code>WHERE column_value = 'All'
  </code></pre>
  <p>2nd one using <code>IN</code> operator and single value</p>
  <pre><code>WHERE column_value IN ('All')
  </code></pre>
  <p>Does SQL engine changes <code>IN</code> to <code>=</code> if only one value is there?</p>
  <p>Is there any difference for same in MySQL and PostgreSQL?</p>