system/classes/Db_MySQL.php
protected function getArrayConditionSep($dataMember, $statementNum, $offset)
    {
        if (isset($this->{$dataMember}[$statementNum][0][$offset][3])) {
            return ' '.$this->{$dataMember}[$statementNum][0][$offset][3].' ';
        }
        return false;
    }
protected function getArrayConditionSep($dataMember, $statementNum, $offset)
    {
        if (isset($this->{$dataMember}[$statementNum][0][$offset][3])) {
            return ' '.$this->{$dataMember}[$statementNum][0][$offset][3].' ';
        }
        return false;
    }
If the optional 4th array parameter denoting the desired conjunction for the next condition is set
within a condition statement, then return that separator.
E.g. the 'OR' below:
[
['id', '>', '100', 'OR'],
['name', 'LIKE', '%s']
]