framework/db/QueryBuilder.php
public function bindParam($value, &$params)
    {
        $phName = self::PARAM_PREFIX . count($params);
        $params[$phName] = $value;

        return $phName;
    }
public function bindParam($value, &$params)
    {
        $phName = self::PARAM_PREFIX . count($params);
        $params[$phName] = $value;

        return $phName;
    }
Helper method to add $value to $params array using [[PARAM_PREFIX]].

@param string|null $value
@param array $params passed by reference
@return string the placeholder name in $params array

@since 2.0.14