mysql a vyhladavanie s diakritikou aj bez

select * from tabulka where pole1 regexp "^[t,T][k,K][a,á,ä,A,Á,Ä][c,C,č,Č]$"

select * from tabulka where pole1 regexp "[t,T][k,K][a,á,ä,A,Á,Ä][c,C,č,Č]"

select * from tabulka where pole1 like "%tkac%" collate "utf8_general_ci"

  function TextToRegtext($text)
  // funkcia prekonvertuje vstupny text po jednom znaku tak ze vzhlada vstupny
  // znak v $sources a do vystupu zapise jeho ekvivalent z $replace. Ak znak nenajde
  // do vystupu zapise zdrojovy znak
  {
    $sources = array("aáäAÁÄ","bB","cCčČ","dDďĎ","eéeëEÉEË",
                     "fF","gG","hH","iIíÍ","jJ","kK","lĺľLĹĽ",
                     "mM","nN","oóöôOÓÖÔ","pP","qQ","rŕřRŔŘ",
                     "sšSŠ","tťTŤ","uúuüUÚUÜ","vV","wW","xX",
                     "yýYÝ","zžZŽ");
    $replace = array("[a,á,ä,A,Á,Ä]","[b,B]","[c,C,č,Č]","[d,D,ď,Ď]","[e,é,e,ë,E,É,E, Ë]",
                     "[f,F]","[g,G]","[h,H]","[i,I,í,Í]","[j,J]","[k,K]","[l,ĺ,ľ,L,Ĺ,Ľ]",
                     "[m,M]","[n,N]","[o,ó,ö,ô,O,Ó,Ö,Ô]","[p,P]","[q,Q]","[r,ŕ,ř,R,Ŕ,Ř]",
                     "[s,š,S,Š]","[t,ť,T,Ť]","[u,ú,u,ü,U,Ú,U,Ü]","[v,V]","[w,W]","[x,X]",
                     "[y,ý,Y,Ý]","[z,ž,Z,Ž]");  
    $regtext = "";
    for ($j = 0; $j < mb_strlen($text,'UTF-8'); $j++)
    {
      for ($k = 0; $k < count($sources); $k++)
      {
        $Decoded = false; 
        if (mb_stristr($sources[$k], mb_substr($text,$j,1,'UTF-8')) != false)
        {
          $regtext = $regtext.$replace[$k];        
          $Decoded = true;
          break;
        }     
      }
      if (!$Decoded)
      {
        $regtext = $regtext."[".mb_substr($text,$j,1,'UTF-8')."]";
      }      
    }
    return $regtext."";  
  }