title: MySQL Illegal mix of collations (utf8_unicode_ci,IMPLICIT) and (utf8_general_ci,IMPLICIT) for operation '='
body: <p>I need your help in identifying why this error is coming</p>
  
  <pre><code>Illegal mix of collations (utf8_unicode_ci,IMPLICIT) and (utf8_general_ci,IMPLICIT) for operation '='
  </code></pre>
  
  <p>The procedure was working fine till yesterday and today it started giving error of
  illegal mix of collations. I checked each and every table of my database and all the tables and its columns are in one charset and collation that is:- utf8 utf8_unicode_ci.</p>
  
  <p>I created another schema with same structrue and tried to execute same query it works fine but not on its original schema. </p>
  
  <p>can anyone provide any input on this? Why is so happening ?</p>