Question: Is there any way to **clear** mysql **query cache** without restarting mySQL server?

Answer: 
I believe you can use...

```
RESET QUERY CACHE;

```

...if the user you're running as has reload rights. Alternatively, you can defragment the query cache via...

```
FLUSH QUERY CACHE;

```

See the [Query Cache Status and Maintenance](http://dev.mysql.com/doc/refman/5.0/en/query-cache-status-and-maintenance.html) section of the MySQL manual for more information.
For anyone else, like myself, looking for a way to clear the query cache and finds this question, the [query cache is deprecated](https://dev.mysql.com/doc/refman/5.7/en/flush.html#flush-query-cache).

> 
> The query cache is deprecated as of MySQL 5.7.20, and is removed in MySQL 8.0.
> 
> 
> 

Therefore the commands `RESET QUERY CACHE` and `FLUSH QUERY CACHE` have been removed.

Have a look at the answers on Database Administrators for more information: [Why did MySQL remove the query cache feature after version 8.0?](https://dba.stackexchange.com/a/217578/1926)