修改pdoQuery方法获取缓存逻辑，和value方法保存一致，避免缓存清空情况导致报错

src/db/PDOConnection.php

@@ -723,10 +723,8 @@ protected function pdoQuery(BaseQuery $query, $sql, bool $master = null): array
             if (!$query->getOptions('force_cache')) {
                 $key = $cacheItem->getKey();
 
-                $data = $this->cache->get($key);
-
-                if (null !== $data) {
-                    return $data;
+                if ($this->cache->has($key)) {
+                    return $this->cache->get($key);
                 }
             }
         }