src/Expression.php
protected function _escape($value)
    {
        // supports array
        if (is_array($value)) {
            return array_map(__METHOD__, $value);
        }

        // in all other cases we should escape
        return
            $this->escape_char
            .str_replace($this->escape_char, $this->escape_char.$this->escape_char, $value)
            .$this->escape_char;
    }
protected function _escape($value)
    {
        // supports array
        if (is_array($value)) {
            return array_map(__METHOD__, $value);
        }

        // in all other cases we should escape
        return
            $this->escape_char
            .str_replace($this->escape_char, $this->escape_char.$this->escape_char, $value)
            .$this->escape_char;
    }
Escapes argument by adding backticks around it.
This will allow you to use reserved SQL words as table or field
names such as "table" as well as other characters that SQL
permits in the identifiers (e.g. spaces or equation signs).

@param mixed $value Any string or array of strings

@return string|array Escaped string or array of strings