public function getColumnAlias($columnName, $counter, AbstractPlatform $platform, ClassMetadata $class = null)
{
// 1 ) Concatenate column name and counter
// 2 ) Trim the column alias to the maximum identifier length of the platform.
// If the alias is to long, characters are cut off from the beginning.
// 3 ) Strip non alphanumeric characters
// 4 ) Prefix with "_" if the result its numeric
$columnName = $columnName . '_' . $counter;
$columnName = substr($columnName, -$platform->getMaxIdentifierLength());
$columnName = preg_replace('/[^A-Za-z0-9_]/', '', $columnName);
$columnName = is_numeric($columnName) ? '_' . $columnName : $columnName;
return $platform->getSQLResultCasing($columnName);
}