+ /**
+ * Escape fields, adding special treatment for "group by" handling
+ *
+ * @param array $fields
+ * @param array $options
+ * @return array Escaped fields
+ */
+ private function escapeFields(array $fields, array $options): array
+ {
+ // In the case of a "GROUP BY" we have to add all the ORDER fields to the fieldlist.
+ // This needs to done to apply the "ANY_VALUE(...)" treatment from below to them.
+ // Otherwise MySQL would report errors.
+ if (!empty($options['group_by']) && !empty($options['order'])) {
+ foreach ($options['order'] as $key => $field) {
+ if (!is_int($key)) {
+ if (!in_array($key, $fields)) {
+ $fields[] = $key;
+ }
+ } else {
+ if (!in_array($field, $fields)) {
+ $fields[] = $field;
+ }
+ }
+ }
+ }
+
+ array_walk($fields, function(&$value, $key) use ($options)
+ {
+ $field = $value;
+ $value = '`' . str_replace('`', '``', $value) . '`';
+
+ if (!empty($options['group_by']) && !in_array($field, $options['group_by'])) {
+ $value = 'ANY_VALUE(' . $value . ') AS ' . $value;
+ }
+ });
+
+ return $fields;
+ }
+