/**
* @param string $alias
* @param string|array $columns
* @param \yii\db\Schema $schema
* @return string
*/
protected function quoteColumn($alias, $columns, $schema)
{
$t = $schema->quoteSimpleTableName($alias);
if (!is_array($columns)) {
return $t . '.' . $schema->quoteSimpleColumnName($columns);
}
$result = array();
foreach ($columns as $column) {
$result[] = $t . '.' . $schema->quoteSimpleColumnName($column);
}
return implode(',', $result);
}