Rsa97

SELECT `id` FROM `object` obj
  JOIN `category` cat ON obj.`id` = obj2.`obj`
  JOIN `obj2cat` obj2 ON obj2.`cat` = cat.`tid` 
  WHERE (
    MATCH(cat.`title`) AGAINST (?)
    OR
    MATCH(obj.`title`) AGAINST (?)
  )

SELECT `id` FROM `object` obj  WHERE MATCH(obj.`title`) AGAINST (?) or tid in (SELECT `tid` FROM `category` cat
  JOIN `obj2cat` obj2 ON obj2.`cat` = cat.`tid` -- мог неверно понять вашу структуру
  WHERE MATCH(cat.`title`) AGAINST (?) )

const string str="asdf";
cout << str[3];  // выведет f, счет в строке с 0.

mysql_connect();
mysql_select_db();
mysql_query();

<th id="sto">100</th>
<td onclick="ChangeColor( this, '#FEEC88' ); ChangeColor( document.getElementById("sto"), '#FEEC88' )">&nbsp;</td>

<th id="sto">100</th>
<td onclick="ChangeColor( [this, document.getElementById("sto")], '#FEEC88' )">&nbsp;</td>

var last_change = [];
var last_color = [];
function ChangeColor( elements, color ){
   if (typeof element !== 'array') {
      elements = [elements];
   }
   for (var i = elements.length; --i;) {
      var element = elements[i];
      if( last_change[element.id] != null ){
          last_change[element.id].style.backgroundColor = last_color[element.id];
      }
      last_change[element.id] = element;
      last_color[element.id] = element.style.backgroundColor;
      element.style.backgroundColor = color;
   }
}

SELECT l . * , f . *